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Sun5i wip #79
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Sun5i wip #79
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This pull request is mostly here https://github.com/amery/linux-allwinner/tree/wip/linux-sunxi-3.0/sun5i |
Verified that https://github.com/amery/linux-allwinner/tree/wip/linux-sunxi-3.0/sun5i boots with cbe599e so closing this pull request. |
amery
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Mar 3, 2013
If start_this_handle() failed handle will be initialized to ERR_PTR() and can not be dereferenced. paging request at fffffffffffffff6 IP: [<ffffffff813c073f>] jbd2__journal_start+0x18f/0x290 PGD 200e067 PUD 200f067 PMD 0 Oops: 0000 [#1] SMP Modules linked in: cpufreq_ondemand acpi_cpufreq freq_table mperf coretemp kvm_intel kvm crc32c_intel ghash_clmulni_intel microcode sg xhci_hcd button sd_mod crc_t10dif aesni_intel ablk_helper cryptd lrw aes_x86_64 xts gf128mul ahci libahci pata_acpi ata_generic dm_mirror dm_region_hash dm_log dm_mod CPU 0 journal commit I/O error Pid: 2694, comm: fio Not tainted 3.8.0-rc3+ #79 /DQ67SW RIP: 0010:[<ffffffff813c073f>] [<ffffffff813c073f>] jbd2__journal_start+0x18f/0x290 RSP: 0018:ffff880233b8ba58 EFLAGS: 00010292 RAX: 00000000ffffffe2 RBX: ffffffffffffffe2 RCX: 0000000000000006 RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffffffff82128f48 RBP: ffff880233b8ba98 R08: 0000000000000000 R09: ffff88021440a6e0 Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
amery
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Nov 12, 2013
Turn it into (for example): [ 0.073380] x86: Booting SMP configuration: [ 0.074005] .... node #0, CPUs: #1 #2 #3 #4 #5 #6 #7 [ 0.603005] .... node #1, CPUs: #8 #9 #10 #11 #12 #13 #14 #15 [ 1.200005] .... node #2, CPUs: #16 #17 #18 #19 #20 #21 #22 #23 [ 1.796005] .... node #3, CPUs: #24 #25 #26 #27 #28 #29 #30 #31 [ 2.393005] .... node #4, CPUs: #32 #33 #34 #35 #36 #37 #38 #39 [ 2.996005] .... node #5, CPUs: #40 #41 #42 #43 #44 #45 #46 #47 [ 3.600005] .... node #6, CPUs: #48 #49 #50 #51 #52 #53 #54 #55 [ 4.202005] .... node #7, CPUs: #56 #57 #58 #59 #60 #61 #62 #63 [ 4.811005] .... node #8, CPUs: #64 #65 #66 #67 #68 #69 #70 #71 [ 5.421006] .... node #9, CPUs: #72 #73 #74 #75 #76 #77 #78 #79 [ 6.032005] .... node #10, CPUs: #80 #81 #82 #83 #84 #85 #86 #87 [ 6.648006] .... node #11, CPUs: #88 #89 #90 #91 #92 #93 #94 #95 [ 7.262005] .... node #12, CPUs: #96 #97 #98 #99 #100 #101 #102 #103 [ 7.865005] .... node #13, CPUs: #104 #105 #106 #107 #108 #109 #110 #111 [ 8.466005] .... node #14, CPUs: #112 #113 #114 #115 #116 #117 #118 #119 [ 9.073006] .... node #15, CPUs: #120 #121 #122 #123 #124 #125 #126 #127 [ 9.679901] x86: Booted up 16 nodes, 128 CPUs and drop useless elements. Change num_digits() to hpa's division-avoiding, cell-phone-typed version which he went at great lengths and pains to submit on a Saturday evening. Signed-off-by: Borislav Petkov <bp@suse.de> Cc: huawei.libin@huawei.com Cc: wangyijing@huawei.com Cc: fenghua.yu@intel.com Cc: guohanjun@huawei.com Cc: paul.gortmaker@windriver.com Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/20130930095624.GB16383@pd.tnic Signed-off-by: Ingo Molnar <mingo@kernel.org>
turl
referenced
this pull request
in allwinner-dev-team/linux-allwinner
Jan 28, 2014
If the driver is unloaded while there is still a host command in flight, its tfd will be freed by iwl_tx_queue_free. This function is called for both types of queues: Tx queues and cmd queue. This didn't take in count the fact that in Tx queues, tfds are mapped as TO_DEVICE (besides the first TB), whereas in cmd queue, all TBs are mapped as BIDI. Hence, tx_queue_free unmapped the second (and higher) TB of each tfd in the cmd queue as TO_DEVICE, whereas they must be freed as BIDI. This means that if a multi TFD is in flight while we unload the driver (which is quite unlikely but can happen), we will get the warning below. This patch fixes this. [ 445.234060] ------------[ cut here ]------------ [ 445.236273] WARNING: at lib/dma-debug.c:861 check_unmap+0x337/0x780() [ 445.236654] iwlagn 0000:02:00.0: DMA-API: device driver frees DMA memory with different direction [device address=0x0000000126950540] [size=8 bytes] [mapped with DMA_BIDIRECTIONAL] [unmapped with DMA_TO_DEVICE] [ 445.236654] Modules linked in: ... [ 445.236654] Pid: 1415, comm: modprobe Not tainted 3.1.0-rc4-wl-65912-g5215ff1-dirty torvalds#79 [ 445.236654] Call Trace: [ 445.236654] [<ffffffff81043a51>] warn_slowpath_common+0x71/0xa0 [ 445.236654] [<ffffffff81043b37>] warn_slowpath_fmt+0x47/0x50 [ 445.236654] [<ffffffff8121e687>] check_unmap+0x337/0x780 [ 445.236654] [<ffffffff810e9136>] ? free_one_page+0x156/0x320 [ 445.236654] [<ffffffff8121ec5a>] debug_dma_unmap_page+0x5a/0x60 [ 445.236654] [<ffffffffa021d701>] iwlagn_unmap_tfd.isra.11+0x121/0x1c0 [iwlagn] [ 445.236654] [<ffffffffa021ddf2>] iwlagn_txq_free_tfd+0x42/0x70 [iwlagn] [ 445.236654] [<ffffffffa02121de>] iwl_tx_queue_unmap+0x4e/0x70 [iwlagn] [ 445.236654] [<ffffffffa0212fad>] iwl_trans_pcie_tx_free+0x10d/0x440 [iwlagn] [ 445.236654] [<ffffffff81064959>] ? destroy_workqueue+0xb9/0x1e0 [ 445.236654] [<ffffffffa021330a>] iwl_trans_pcie_free+0x2a/0x2c0 [iwlagn] [ 445.236654] [<ffffffffa022f4f2>] iwl_remove+0x149/0x17e [iwlagn] [ 445.236654] [<ffffffffa022f546>] iwl_pci_remove+0x1f/0x65 [iwlagn] [ 445.236654] [<ffffffff81228337>] pci_device_remove+0x47/0x120 [ 445.236654] [<ffffffff8134566c>] __device_release_driver+0x7c/0xe0 [ 445.236654] [<ffffffff81345dc8>] driver_detach+0xc8/0xd0 [ 445.236654] [<ffffffff813454c8>] bus_remove_driver+0x88/0xe0 [ 445.236654] [<ffffffff81346572>] driver_unregister+0x62/0xa0 [ 445.236654] [<ffffffff812271d4>] pci_unregister_driver+0x44/0xc0 [ 445.236654] [<ffffffffa0211ce5>] iwl_pci_unregister_driver+0x15/0x20 [iwlagn] [ 445.236654] [<ffffffffa022f595>] iwl_exit+0x9/0xa74 [iwlagn] [ 445.236654] [<ffffffff810918f4>] sys_delete_module+0x184/0x240 [ 445.236654] [<ffffffff81452ece>] ? retint_swapgs+0xe/0x13 [ 445.236654] [<ffffffff8121098e>] ? trace_hardirqs_on_thunk+0x3a/0x3f [ 445.236654] [<ffffffff81459e2b>] system_call_fastpath+0x16/0x1b [ 445.236654] ---[ end trace 1fbc362b7dbe5d74 ]--- [ 445.236654] Mapped at: [ 445.236654] [<ffffffff8121d7cb>] debug_dma_map_page+0x8b/0x150 [ 445.236654] [<ffffffffa021e7b7>] iwl_enqueue_hcmd+0x837/0xa40 [iwlagn] [ 445.236654] [<ffffffffa021f92d>] iwl_trans_pcie_send_cmd+0x8d/0x580 [iwlagn] [ 445.236654] [<ffffffffa01f7c75>] iwl_send_calib_results+0x75/0xd0 [iwlagn] [ 445.236654] [<ffffffffa01f21f6>] iwlagn_alive_notify+0x196/0x1f0 [iwlagn] [ 445.386500] iwlagn 0000:02:00.0: PCI INT A disabled Reported-by: Johannes Berg <johannes.berg@intel.com> Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com> Signed-off-by: Wey-Yi Guy <wey-yi.w.guy@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
ssvb
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to ssvb/linux-sunxi
that referenced
this pull request
May 2, 2014
commit 1cd9f09 upstream. This doesn't make much sense, and it exposes a bug in the kernel where attempts to create a new file in an append-only directory using O_CREAT will fail (but still leave a zero-length file). This was discovered when xfstests linux-sunxi#79 was generalized so it could run on all file systems. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
amery
pushed a commit
that referenced
this pull request
Feb 22, 2016
When using a 5G-capable device with VHT (802.11ac) rates enabled was not working (packets were not delivered) and the following mac80211 warning was printed: WARNING: CPU: 3 PID: 2253 at net/mac80211/rate.c:625 ieee80211_get_tx_rates+0x22e/0x620 [mac80211]() Modules linked in: rtl8821ae btcoexist rtl_pci rtlwifi fuse drbg ansi_cprng ctr ccm bnep bluetooth af_packet nfs fscache vboxpci(O) vboxnetadp(O) vboxne tflt(O) vboxdrv(O) arc4 snd_hda_codec_generic x86_pkg_temp_thermal rtsx_pci_sdmmc mmc_core rtsx_pci_ms kvm_intel memstick iwlmvm kvm mac80211 snd_hda_intel snd_hda_cod ec snd_hwdep snd_hda_core irqbypass snd_pcm iwlwifi crct10dif_pclmul crc32_pclmul crc32c_intel ghash_clmulni_intel aesni_intel aes_x86_64 snd_timer lrw gf128mul glue_h elper ablk_helper cryptd snd cfg80211 pcspkr serio_raw e1000e rtsx_pci lpc_ich ptp xhci_pci mfd_core pps_core xhci_hcd soundcore toshiba_acpi thermal sparse_keymap wmi toshiba_bluetooth rfkill acpi_cpufreq battery ac processor dm_mod i915 i2c_algo_bit drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm sr_mod cdrom video button sg autofs4 [last unloaded: rtlwifi] CPU: 3 PID: 2253 Comm: Timer Tainted: G W O 4.5.0-rc1-wl+ #79 Hardware name: TOSHIBA TECRA A50-A/TECRA A50-A, BIOS Version 4.20 04/17/2014 ffffffffa05c4be6 ffff8802262036d8 ffffffff813d7912 0000000000000000 ffff880226203710 ffffffff8106bcb6 ffff8800c6831300 ffff8800c6831330 0000000000000000 ffff8800c683133c ffff880065923638 ffff880226203720 Call Trace: <IRQ> [<ffffffff813d7912>] dump_stack+0x4b/0x79 [<ffffffff8106bcb6>] warn_slowpath_common+0x86/0xc0 [<ffffffff8106bdaa>] warn_slowpath_null+0x1a/0x20 [<ffffffffa05511ee>] ieee80211_get_tx_rates+0x22e/0x620 [mac80211] [<ffffffffa0782232>] ? rtl_is_special_data+0x32/0x240 [rtlwifi] [<ffffffffa055209e>] ? rate_control_get_rate+0xce/0x150 [mac80211] [<ffffffff810bfc7d>] ? trace_hardirqs_on+0xd/0x10 [<ffffffff81071cc5>] ? __local_bh_enable_ip+0x65/0xd0 Signed-off-by: Kalle Valo <kvalo@codeaurora.org>
amery
pushed a commit
that referenced
this pull request
Jan 5, 2017
__skb_flow_dissect can be called with a skb or a data packet, either can be NULL. All calls seems to have been moved to __skb_header_pointer except the pptp handling which is still calling skb_header_pointer. skb_header_pointer will use skb->data and thus: [ 109.556866] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 109.557102] IP: [<ffffffff88dc02f8>] __skb_flow_dissect+0xa88/0xce0 [ 109.557263] PGD 0 [ 109.557338] [ 109.557484] Oops: 0000 [#1] SMP [ 109.557562] Modules linked in: chaoskey [ 109.557783] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.9.0 #79 [ 109.557867] Hardware name: Supermicro A1SRM-LN7F/LN5F/A1SRM-LN7F-2758, BIOS 1.0c 11/04/2015 [ 109.557957] task: ffff94085c27bc00 task.stack: ffffb745c0068000 [ 109.558041] RIP: 0010:[<ffffffff88dc02f8>] [<ffffffff88dc02f8>] __skb_flow_dissect+0xa88/0xce0 [ 109.558203] RSP: 0018:ffff94087fc83d40 EFLAGS: 00010206 [ 109.558286] RAX: 0000000000000130 RBX: ffffffff8975bf80 RCX: ffff94084fab6800 [ 109.558373] RDX: 0000000000000010 RSI: 000000000000000c RDI: 0000000000000000 [ 109.558460] RBP: 0000000000000b88 R08: 0000000000000000 R09: 0000000000000022 [ 109.558547] R10: 0000000000000008 R11: ffff94087fc83e04 R12: 0000000000000000 [ 109.558763] R13: ffff94084fab6800 R14: ffff94087fc83e04 R15: 000000000000002f [ 109.558979] FS: 0000000000000000(0000) GS:ffff94087fc80000(0000) knlGS:0000000000000000 [ 109.559326] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 109.559539] CR2: 0000000000000080 CR3: 0000000281809000 CR4: 00000000001026e0 [ 109.559753] Stack: [ 109.559957] 000000000000000c ffff94084fab6822 0000000000000001 ffff94085c2b5fc0 [ 109.560578] 0000000000000001 0000000000002000 0000000000000000 0000000000000000 [ 109.561200] 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 109.561820] Call Trace: [ 109.562027] <IRQ> [ 109.562108] [<ffffffff88dfb4fa>] ? eth_get_headlen+0x7a/0xf0 [ 109.562522] [<ffffffff88c5a35a>] ? igb_poll+0x96a/0xe80 [ 109.562737] [<ffffffff88dc912b>] ? net_rx_action+0x20b/0x350 [ 109.562953] [<ffffffff88546d68>] ? __do_softirq+0xe8/0x280 [ 109.563169] [<ffffffff8854704a>] ? irq_exit+0xaa/0xb0 [ 109.563382] [<ffffffff8847229b>] ? do_IRQ+0x4b/0xc0 [ 109.563597] [<ffffffff8902d4ff>] ? common_interrupt+0x7f/0x7f [ 109.563810] <EOI> [ 109.563890] [<ffffffff88d57530>] ? cpuidle_enter_state+0x130/0x2c0 [ 109.564304] [<ffffffff88d57520>] ? cpuidle_enter_state+0x120/0x2c0 [ 109.564520] [<ffffffff8857eacf>] ? cpu_startup_entry+0x19f/0x1f0 [ 109.564737] [<ffffffff8848d55a>] ? start_secondary+0x12a/0x140 [ 109.564950] Code: 83 e2 20 a8 80 0f 84 60 01 00 00 c7 04 24 08 00 00 00 66 85 d2 0f 84 be fe ff ff e9 69 fe ff ff 8b 34 24 89 f2 83 c2 04 66 85 c0 <41> 8b 84 24 80 00 00 00 0f 49 d6 41 8d 31 01 d6 41 2b 84 24 84 [ 109.569959] RIP [<ffffffff88dc02f8>] __skb_flow_dissect+0xa88/0xce0 [ 109.570245] RSP <ffff94087fc83d40> [ 109.570453] CR2: 0000000000000080 Fixes: ab10dcc ("rps: Inspect PPTP encapsulated by GRE to get flow hash") Signed-off-by: Ian Kumlien <ian.kumlien@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
repojohnray
pushed a commit
to repojohnray/linux-sunxi-4.7.y
that referenced
this pull request
Jan 15, 2017
[ Upstream commit d0af683 ] __skb_flow_dissect can be called with a skb or a data packet, either can be NULL. All calls seems to have been moved to __skb_header_pointer except the pptp handling which is still calling skb_header_pointer. skb_header_pointer will use skb->data and thus: [ 109.556866] BUG: unable to handle kernel NULL pointer dereference at 0000000000000080 [ 109.557102] IP: [<ffffffff88dc02f8>] __skb_flow_dissect+0xa88/0xce0 [ 109.557263] PGD 0 [ 109.557338] [ 109.557484] Oops: 0000 [jwrdegoede#1] SMP [ 109.557562] Modules linked in: chaoskey [ 109.557783] CPU: 2 PID: 0 Comm: swapper/2 Not tainted 4.9.0 linux-sunxi#79 [ 109.557867] Hardware name: Supermicro A1SRM-LN7F/LN5F/A1SRM-LN7F-2758, BIOS 1.0c 11/04/2015 [ 109.557957] task: ffff94085c27bc00 task.stack: ffffb745c0068000 [ 109.558041] RIP: 0010:[<ffffffff88dc02f8>] [<ffffffff88dc02f8>] __skb_flow_dissect+0xa88/0xce0 [ 109.558203] RSP: 0018:ffff94087fc83d40 EFLAGS: 00010206 [ 109.558286] RAX: 0000000000000130 RBX: ffffffff8975bf80 RCX: ffff94084fab6800 [ 109.558373] RDX: 0000000000000010 RSI: 000000000000000c RDI: 0000000000000000 [ 109.558460] RBP: 0000000000000b88 R08: 0000000000000000 R09: 0000000000000022 [ 109.558547] R10: 0000000000000008 R11: ffff94087fc83e04 R12: 0000000000000000 [ 109.558763] R13: ffff94084fab6800 R14: ffff94087fc83e04 R15: 000000000000002f [ 109.558979] FS: 0000000000000000(0000) GS:ffff94087fc80000(0000) knlGS:0000000000000000 [ 109.559326] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 109.559539] CR2: 0000000000000080 CR3: 0000000281809000 CR4: 00000000001026e0 [ 109.559753] Stack: [ 109.559957] 000000000000000c ffff94084fab6822 0000000000000001 ffff94085c2b5fc0 [ 109.560578] 0000000000000001 0000000000002000 0000000000000000 0000000000000000 [ 109.561200] 0000000000000000 0000000000000000 0000000000000000 0000000000000000 [ 109.561820] Call Trace: [ 109.562027] <IRQ> [ 109.562108] [<ffffffff88dfb4fa>] ? eth_get_headlen+0x7a/0xf0 [ 109.562522] [<ffffffff88c5a35a>] ? igb_poll+0x96a/0xe80 [ 109.562737] [<ffffffff88dc912b>] ? net_rx_action+0x20b/0x350 [ 109.562953] [<ffffffff88546d68>] ? __do_softirq+0xe8/0x280 [ 109.563169] [<ffffffff8854704a>] ? irq_exit+0xaa/0xb0 [ 109.563382] [<ffffffff8847229b>] ? do_IRQ+0x4b/0xc0 [ 109.563597] [<ffffffff8902d4ff>] ? common_interrupt+0x7f/0x7f [ 109.563810] <EOI> [ 109.563890] [<ffffffff88d57530>] ? cpuidle_enter_state+0x130/0x2c0 [ 109.564304] [<ffffffff88d57520>] ? cpuidle_enter_state+0x120/0x2c0 [ 109.564520] [<ffffffff8857eacf>] ? cpu_startup_entry+0x19f/0x1f0 [ 109.564737] [<ffffffff8848d55a>] ? start_secondary+0x12a/0x140 [ 109.564950] Code: 83 e2 20 a8 80 0f 84 60 01 00 00 c7 04 24 08 00 00 00 66 85 d2 0f 84 be fe ff ff e9 69 fe ff ff 8b 34 24 89 f2 83 c2 04 66 85 c0 <41> 8b 84 24 80 00 00 00 0f 49 d6 41 8d 31 01 d6 41 2b 84 24 84 [ 109.569959] RIP [<ffffffff88dc02f8>] __skb_flow_dissect+0xa88/0xce0 [ 109.570245] RSP <ffff94087fc83d40> [ 109.570453] CR2: 0000000000000080 Fixes: ab10dcc ("rps: Inspect PPTP encapsulated by GRE to get flow hash") Signed-off-by: Ian Kumlien <ian.kumlien@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
wens
pushed a commit
that referenced
this pull request
Mar 17, 2019
When setting /sys/fs/f2fs/<DEV>/iostat_enable with non-bool value, UBSAN reports the following warning. [ 7562.295484] ================================================================================ [ 7562.296531] UBSAN: Undefined behaviour in fs/f2fs/f2fs.h:2776:10 [ 7562.297651] load of value 64 is not a valid value for type '_Bool' [ 7562.298642] CPU: 1 PID: 7487 Comm: dd Not tainted 4.20.0-rc4+ #79 [ 7562.298653] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 7562.298662] Call Trace: [ 7562.298760] dump_stack+0x46/0x5b [ 7562.298811] ubsan_epilogue+0x9/0x40 [ 7562.298830] __ubsan_handle_load_invalid_value+0x72/0x90 [ 7562.298863] f2fs_file_write_iter+0x29f/0x3f0 [ 7562.298905] __vfs_write+0x115/0x160 [ 7562.298922] vfs_write+0xa7/0x190 [ 7562.298934] ksys_write+0x50/0xc0 [ 7562.298973] do_syscall_64+0x4a/0xe0 [ 7562.298992] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 7562.299001] RIP: 0033:0x7fa45ec19c00 [ 7562.299004] Code: 73 01 c3 48 8b 0d 88 92 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d dd eb 2c 00 00 75 10 b8 01 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ce 8f 01 00 48 89 04 24 [ 7562.299044] RSP: 002b:00007ffca52b49e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 7562.299052] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa45ec19c00 [ 7562.299059] RDX: 0000000000000400 RSI: 000000000093f000 RDI: 0000000000000001 [ 7562.299065] RBP: 000000000093f000 R08: 0000000000000004 R09: 0000000000000000 [ 7562.299071] R10: 00007ffca52b47b0 R11: 0000000000000246 R12: 0000000000000400 [ 7562.299077] R13: 000000000093f000 R14: 000000000093f400 R15: 0000000000000000 [ 7562.299091] ================================================================================ So, if iostat_enable is enabled, set its value as true. Signed-off-by: Sheng Yong <shengyong1@huawei.com> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
repojohnray
pushed a commit
to repojohnray/linux-sunxi-4.7.y
that referenced
this pull request
Apr 6, 2019
[ Upstream commit ac92985 ] When setting /sys/fs/f2fs/<DEV>/iostat_enable with non-bool value, UBSAN reports the following warning. [ 7562.295484] ================================================================================ [ 7562.296531] UBSAN: Undefined behaviour in fs/f2fs/f2fs.h:2776:10 [ 7562.297651] load of value 64 is not a valid value for type '_Bool' [ 7562.298642] CPU: 1 PID: 7487 Comm: dd Not tainted 4.20.0-rc4+ linux-sunxi#79 [ 7562.298653] Hardware name: innotek GmbH VirtualBox/VirtualBox, BIOS VirtualBox 12/01/2006 [ 7562.298662] Call Trace: [ 7562.298760] dump_stack+0x46/0x5b [ 7562.298811] ubsan_epilogue+0x9/0x40 [ 7562.298830] __ubsan_handle_load_invalid_value+0x72/0x90 [ 7562.298863] f2fs_file_write_iter+0x29f/0x3f0 [ 7562.298905] __vfs_write+0x115/0x160 [ 7562.298922] vfs_write+0xa7/0x190 [ 7562.298934] ksys_write+0x50/0xc0 [ 7562.298973] do_syscall_64+0x4a/0xe0 [ 7562.298992] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 7562.299001] RIP: 0033:0x7fa45ec19c00 [ 7562.299004] Code: 73 01 c3 48 8b 0d 88 92 2c 00 f7 d8 64 89 01 48 83 c8 ff c3 66 0f 1f 44 00 00 83 3d dd eb 2c 00 00 75 10 b8 01 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ce 8f 01 00 48 89 04 24 [ 7562.299044] RSP: 002b:00007ffca52b49e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 [ 7562.299052] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fa45ec19c00 [ 7562.299059] RDX: 0000000000000400 RSI: 000000000093f000 RDI: 0000000000000001 [ 7562.299065] RBP: 000000000093f000 R08: 0000000000000004 R09: 0000000000000000 [ 7562.299071] R10: 00007ffca52b47b0 R11: 0000000000000246 R12: 0000000000000400 [ 7562.299077] R13: 000000000093f000 R14: 000000000093f400 R15: 0000000000000000 [ 7562.299091] ================================================================================ So, if iostat_enable is enabled, set its value as true. Signed-off-by: Sheng Yong <shengyong1@huawei.com> Reviewed-by: Chao Yu <yuchao0@huawei.com> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
repojohnray
pushed a commit
to repojohnray/linux-sunxi-4.7.y
that referenced
this pull request
May 2, 2019
commit 032be5f upstream. After commit 5271953 ("rxrpc: Use the UDP encap_rcv hook"), rxrpc_input_packet() is directly called from lockless UDP receive path, under rcu_read_lock() protection. It must therefore use RCU rules : - udp_sk->sk_user_data can be cleared at any point in this function. rcu_dereference_sk_user_data() is what we need here. - Also, since sk_user_data might have been set in rxrpc_open_socket() we must observe a proper RCU grace period before kfree(local) in rxrpc_lookup_local() v4: @Local can be NULL in xrpc_lookup_local() as reported by kbuild test robot <lkp@intel.com> and Julia Lawall <julia.lawall@lip6.fr>, thanks ! v3,v2 : addressed David Howells feedback, thanks ! syzbot reported : kasan: CONFIG_KASAN_INLINE enabled kasan: GPF could be caused by NULL-ptr deref or user memory access general protection fault: 0000 [jwrdegoede#1] PREEMPT SMP KASAN CPU: 0 PID: 19236 Comm: syz-executor703 Not tainted 5.1.0-rc6 linux-sunxi#79 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:__lock_acquire+0xbef/0x3fb0 kernel/locking/lockdep.c:3573 Code: 00 0f 85 a5 1f 00 00 48 81 c4 10 01 00 00 5b 41 5c 41 5d 41 5e 41 5f 5d c3 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 <80> 3c 02 00 0f 85 4a 21 00 00 49 81 7d 00 20 54 9c 89 0f 84 cf f4 RSP: 0018:ffff88809d7aef58 EFLAGS: 00010002 RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000000026 RSI: 0000000000000000 RDI: 0000000000000001 RBP: ffff88809d7af090 R08: 0000000000000001 R09: 0000000000000001 R10: ffffed1015d05bc7 R11: ffff888089428600 R12: 0000000000000000 R13: 0000000000000130 R14: 0000000000000001 R15: 0000000000000001 FS: 00007f059044d700(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00000000004b6040 CR3: 00000000955ca000 CR4: 00000000001406f0 Call Trace: lock_acquire+0x16f/0x3f0 kernel/locking/lockdep.c:4211 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:152 skb_queue_tail+0x26/0x150 net/core/skbuff.c:2972 rxrpc_reject_packet net/rxrpc/input.c:1126 [inline] rxrpc_input_packet+0x4a0/0x5536 net/rxrpc/input.c:1414 udp_queue_rcv_one_skb+0xaf2/0x1780 net/ipv4/udp.c:2011 udp_queue_rcv_skb+0x128/0x730 net/ipv4/udp.c:2085 udp_unicast_rcv_skb.isra.0+0xb9/0x360 net/ipv4/udp.c:2245 __udp4_lib_rcv+0x701/0x2ca0 net/ipv4/udp.c:2301 udp_rcv+0x22/0x30 net/ipv4/udp.c:2482 ip_protocol_deliver_rcu+0x60/0x8f0 net/ipv4/ip_input.c:208 ip_local_deliver_finish+0x23b/0x390 net/ipv4/ip_input.c:234 NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] ip_local_deliver+0x1e9/0x520 net/ipv4/ip_input.c:255 dst_input include/net/dst.h:450 [inline] ip_rcv_finish+0x1e1/0x300 net/ipv4/ip_input.c:413 NF_HOOK include/linux/netfilter.h:289 [inline] NF_HOOK include/linux/netfilter.h:283 [inline] ip_rcv+0xe8/0x3f0 net/ipv4/ip_input.c:523 __netif_receive_skb_one_core+0x115/0x1a0 net/core/dev.c:4987 __netif_receive_skb+0x2c/0x1c0 net/core/dev.c:5099 netif_receive_skb_internal+0x117/0x660 net/core/dev.c:5202 napi_frags_finish net/core/dev.c:5769 [inline] napi_gro_frags+0xade/0xd10 net/core/dev.c:5843 tun_get_user+0x2f24/0x3fb0 drivers/net/tun.c:1981 tun_chr_write_iter+0xbd/0x156 drivers/net/tun.c:2027 call_write_iter include/linux/fs.h:1866 [inline] do_iter_readv_writev+0x5e1/0x8e0 fs/read_write.c:681 do_iter_write fs/read_write.c:957 [inline] do_iter_write+0x184/0x610 fs/read_write.c:938 vfs_writev+0x1b3/0x2f0 fs/read_write.c:1002 do_writev+0x15e/0x370 fs/read_write.c:1037 __do_sys_writev fs/read_write.c:1110 [inline] __se_sys_writev fs/read_write.c:1107 [inline] __x64_sys_writev+0x75/0xb0 fs/read_write.c:1107 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe Fixes: 5271953 ("rxrpc: Use the UDP encap_rcv hook") Signed-off-by: Eric Dumazet <edumazet@google.com> Reported-by: syzbot <syzkaller@googlegroups.com> Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
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Aug 10, 2019
FIXME [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** [ 6.713296] 4 locks held by kworker/0:1/7: [ 6.713305] #0: 00000000e50bf679 ((wq_completion)events){+.+.}, at: process_one_work+0x1b1/0x560 [ 6.713326] #1: 000000004becbc72 (deferred_probe_work){+.+.}, at: process_one_work+0x1b1/0x560 [ 6.713347] #2: 00000000bac55438 (&dev->mutex){....}, at: __device_attach+0x36/0x170 [ 6.713368] #3: 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.713391] stack backtrace: [ 6.713404] CPU: 0 PID: 7 Comm: kworker/0:1 Not tainted 5.3.0-rc2+ linux-sunxi#79 [ 6.713416] Hardware name: Insyde BayTrail/0E57, BIOS A06W328S04_P2AC2G 11/04/2063 [ 6.713434] Workqueue: events deferred_probe_work_func [ 6.713446] Call Trace: [ 6.713462] dump_stack+0x85/0xc8 [ 6.713475] check_noncircular+0x17e/0x1b0 [ 6.713491] __lock_acquire+0xe07/0x1930 [ 6.713506] lock_acquire+0x9d/0x1a0 [ 6.713518] ? iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713534] __mutex_lock+0xa8/0x9a0 [ 6.713546] ? iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713561] ? iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713578] ? iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713591] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713605] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713617] i2c_dw_probe+0x57/0x473 [ 6.713630] dw_i2c_plat_probe+0x33e/0x640 [ 6.713645] platform_drv_probe+0x38/0x80 [ 6.713658] really_probe+0xf3/0x380 [ 6.713670] driver_probe_device+0x59/0xd0 [ 6.713683] ? driver_allows_async_probing+0x50/0x50 [ 6.713695] bus_for_each_drv+0x84/0xd0 [ 6.713708] __device_attach+0xe4/0x170 [ 6.713722] bus_probe_device+0x9f/0xb0 [ 6.713734] deferred_probe_work_func+0x79/0xd0 [ 6.713746] process_one_work+0x234/0x560 [ 6.713761] worker_thread+0x50/0x3b0 [ 6.713775] kthread+0x10a/0x140 [ 6.713785] ? process_one_work+0x560/0x560 [ 6.713797] ? kthread_park+0x80/0x80 [ 6.713810] ret_from_fork+0x3a/0x50 FIXME Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
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Aug 11, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Aug 13, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
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this pull request
Aug 15, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Aug 15, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Aug 16, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Aug 16, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Aug 17, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Aug 18, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Aug 22, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Aug 27, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Aug 28, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Aug 30, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Sep 5, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Sep 7, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Sep 7, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Sep 14, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Sep 18, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Sep 18, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
jwrdegoede
added a commit
to jwrdegoede/linux-sunxi
that referenced
this pull request
Sep 21, 2019
There are 2 problems with the old iosf PMIC I2C bus arbritration code which this commit fixes: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> #1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. This commit fixes this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
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Oct 7, 2019
[ Upstream commit 00452ba ] There are 2 problems with the old iosf PMIC I2C bus arbritration code which need to be addressed: 1. The lockdep code complains about a possible deadlock in the iosf_mbi_[un]block_punit_i2c_access code: [ 6.712662] ====================================================== [ 6.712673] WARNING: possible circular locking dependency detected [ 6.712685] 5.3.0-rc2+ linux-sunxi#79 Not tainted [ 6.712692] ------------------------------------------------------ [ 6.712702] kworker/0:1/7 is trying to acquire lock: [ 6.712712] 00000000df1c5681 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}, at: iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.712739] but task is already holding lock: [ 6.712749] 0000000067cb23e7 (iosf_mbi_punit_mutex){+.+.}, at: iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712768] which lock already depends on the new lock. [ 6.712780] the existing dependency chain (in reverse order) is: [ 6.712792] -> jwrdegoede#1 (iosf_mbi_punit_mutex){+.+.}: [ 6.712808] __mutex_lock+0xa8/0x9a0 [ 6.712818] iosf_mbi_block_punit_i2c_access+0x97/0x186 [ 6.712831] i2c_dw_acquire_lock+0x20/0x30 [ 6.712841] i2c_dw_set_reg_access+0x15/0xb0 [ 6.712851] i2c_dw_probe+0x57/0x473 [ 6.712861] dw_i2c_plat_probe+0x33e/0x640 [ 6.712874] platform_drv_probe+0x38/0x80 [ 6.712884] really_probe+0xf3/0x380 [ 6.712894] driver_probe_device+0x59/0xd0 [ 6.712905] bus_for_each_drv+0x84/0xd0 [ 6.712915] __device_attach+0xe4/0x170 [ 6.712925] bus_probe_device+0x9f/0xb0 [ 6.712935] deferred_probe_work_func+0x79/0xd0 [ 6.712946] process_one_work+0x234/0x560 [ 6.712957] worker_thread+0x50/0x3b0 [ 6.712967] kthread+0x10a/0x140 [ 6.712977] ret_from_fork+0x3a/0x50 [ 6.712986] -> #0 (iosf_mbi_block_punit_i2c_access_count_mutex){+.+.}: [ 6.713004] __lock_acquire+0xe07/0x1930 [ 6.713015] lock_acquire+0x9d/0x1a0 [ 6.713025] __mutex_lock+0xa8/0x9a0 [ 6.713035] iosf_mbi_unblock_punit_i2c_access+0x13/0x90 [ 6.713047] i2c_dw_set_reg_access+0x4d/0xb0 [ 6.713058] i2c_dw_probe+0x57/0x473 [ 6.713068] dw_i2c_plat_probe+0x33e/0x640 [ 6.713079] platform_drv_probe+0x38/0x80 [ 6.713089] really_probe+0xf3/0x380 [ 6.713099] driver_probe_device+0x59/0xd0 [ 6.713109] bus_for_each_drv+0x84/0xd0 [ 6.713119] __device_attach+0xe4/0x170 [ 6.713129] bus_probe_device+0x9f/0xb0 [ 6.713140] deferred_probe_work_func+0x79/0xd0 [ 6.713150] process_one_work+0x234/0x560 [ 6.713160] worker_thread+0x50/0x3b0 [ 6.713170] kthread+0x10a/0x140 [ 6.713180] ret_from_fork+0x3a/0x50 [ 6.713189] other info that might help us debug this: [ 6.713202] Possible unsafe locking scenario: [ 6.713212] CPU0 CPU1 [ 6.713221] ---- ---- [ 6.713229] lock(iosf_mbi_punit_mutex); [ 6.713239] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713253] lock(iosf_mbi_punit_mutex); [ 6.713265] lock(iosf_mbi_block_punit_i2c_access_count_mutex); [ 6.713276] *** DEADLOCK *** In practice can never happen because only the first caller which increments iosf_mbi_block_punit_i2c_access_count will also take iosf_mbi_punit_mutex, that is the whole purpose of the counter, which itself is protected by iosf_mbi_block_punit_i2c_access_count_mutex. But there is no way to tell the lockdep code about this and we really want to be able to run a kernel with lockdep enabled without these warnings being triggered. 2. The lockdep warning also points out another real problem, if 2 threads both are in a block of code protected by iosf_mbi_block_punit_i2c_access and the first thread to acquire the block exits before the second thread then the second thread will call mutex_unlock on iosf_mbi_punit_mutex, but it is not the thread which took the mutex and unlocking by another thread is not allowed. Fix this by getting rid of the notion of holding a mutex for the entire duration of the PMIC accesses, be it either from the PUnit side, or from an in kernel I2C driver. In general holding a mutex after exiting a function is a bad idea and the above problems show this case is no different. Instead 2 counters are now used, one for PMIC accesses from the PUnit and one for accesses from in kernel I2C code. When access is requested now the code will wait (using a waitqueue) for the counter of the other type of access to reach 0 and on release, if the counter reaches 0 the wakequeue is woken. Note that the counter approach is necessary to allow nested calls. The main reason for this is so that a series of i2c transfers can be done with the punit blocked from accessing the bus the whole time. This is necessary to be able to safely read/modify/write a PMIC register without racing with the PUNIT doing the same thing. Allowing nested iosf_mbi_block_punit_i2c_access() calls also is desirable from a performance pov since the whole dance necessary to block the PUnit from accessing the PMIC I2C bus is somewhat expensive. Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Link: https://lkml.kernel.org/r/20190812102113.95794-1-hdegoede@redhat.com Signed-off-by: Sasha Levin <sashal@kernel.org>
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Mar 11, 2020
Stefan reported a strange kernel fault which turned out to be due to a missing KUAP disable in flush_coherent_icache() called from flush_icache_range(). The fault looks like: Kernel attempted to access user page (7fffc30d9c00) - exploit attempt? (uid: 1009) BUG: Unable to handle kernel data access on read at 0x7fffc30d9c00 Faulting instruction address: 0xc00000000007232c Oops: Kernel access of bad area, sig: 11 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA PowerNV CPU: 35 PID: 5886 Comm: sigtramp Not tainted 5.6.0-rc2-gcc-8.2.0-00003-gfc37a1632d40 linux-sunxi#79 NIP: c00000000007232c LR: c00000000003b7fc CTR: 0000000000000000 REGS: c000001e11093940 TRAP: 0300 Not tainted (5.6.0-rc2-gcc-8.2.0-00003-gfc37a1632d40) MSR: 900000000280b033 <SF,HV,VEC,VSX,EE,FP,ME,IR,DR,RI,LE> CR: 28000884 XER: 00000000 CFAR: c0000000000722fc DAR: 00007fffc30d9c00 DSISR: 08000000 IRQMASK: 0 GPR00: c00000000003b7fc c000001e11093bd0 c0000000023ac200 00007fffc30d9c00 GPR04: 00007fffc30d9c18 0000000000000000 c000001e11093bd4 0000000000000000 GPR08: 0000000000000000 0000000000000001 0000000000000000 c000001e1104ed80 GPR12: 0000000000000000 c000001fff6ab380 c0000000016be2d0 4000000000000000 GPR16: c000000000000000 bfffffffffffffff 0000000000000000 0000000000000000 GPR20: 00007fffc30d9c00 00007fffc30d8f58 00007fffc30d9c18 00007fffc30d9c20 GPR24: 00007fffc30d9c18 0000000000000000 c000001e11093d90 c000001e1104ed80 GPR28: c000001e11093e90 0000000000000000 c0000000023d9d18 00007fffc30d9c00 NIP flush_icache_range+0x5c/0x80 LR handle_rt_signal64+0x95c/0xc2c Call Trace: 0xc000001e11093d90 (unreliable) handle_rt_signal64+0x93c/0xc2c do_notify_resume+0x310/0x430 ret_from_except_lite+0x70/0x74 Instruction dump: 409e002c 7c0802a6 3c62ff31 3863f6a0 f8010080 48195fed 60000000 48fe4c8d 60000000 e8010080 7c0803a6 7c0004ac <7c00ffac> 7c0004ac 4c00012c 38210070 This path through handle_rt_signal64() to setup_trampoline() and flush_icache_range() is only triggered by 64-bit processes that have unmapped their VDSO, which is rare. flush_icache_range() takes a range of addresses to flush. In flush_coherent_icache() we implement an optimisation for CPUs where we know we don't actually have to flush the whole range, we just need to do a single icbi. However we still execute the icbi on the user address of the start of the range we're flushing. On CPUs that also implement KUAP (Power9) that leads to the spurious fault above. We should be able to pass any address, including a kernel address, to the icbi on these CPUs, which would avoid any interaction with KUAP. But I don't want to make that change in a bug fix, just in case it surfaces some strange behaviour on some CPU. So for now just disable KUAP around the icbi. Note the icbi is treated as a load, so we allow read access, not write as you'd expect. Fixes: 890274c ("powerpc/64s: Implement KUAP for Radix MMU") Cc: stable@vger.kernel.org # v5.2+ Reported-by: Stefan Berger <stefanb@linux.ibm.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20200303235708.26004-1-mpe@ellerman.id.au
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Apr 25, 2022
…e_zone commit 0b9e667 upstream. btrfs_can_activate_zone() can be called with the device_list_mutex already held, which will lead to a deadlock: insert_dev_extents() // Takes device_list_mutex `-> insert_dev_extent() `-> btrfs_insert_empty_item() `-> btrfs_insert_empty_items() `-> btrfs_search_slot() `-> btrfs_cow_block() `-> __btrfs_cow_block() `-> btrfs_alloc_tree_block() `-> btrfs_reserve_extent() `-> find_free_extent() `-> find_free_extent_update_loop() `-> can_allocate_chunk() `-> btrfs_can_activate_zone() // Takes device_list_mutex again Instead of using the RCU on fs_devices->device_list we can use fs_devices->alloc_list, protected by the chunk_mutex to traverse the list of active devices. We are in the chunk allocation thread. The newer chunk allocation happens from the devices in the fs_device->alloc_list protected by the chunk_mutex. btrfs_create_chunk() lockdep_assert_held(&info->chunk_mutex); gather_device_info list_for_each_entry(device, &fs_devices->alloc_list, dev_alloc_list) Also, a device that reappears after the mount won't join the alloc_list yet and, it will be in the dev_list, which we don't want to consider in the context of the chunk alloc. [15.166572] WARNING: possible recursive locking detected [15.167117] 5.17.0-rc6-dennis linux-sunxi#79 Not tainted [15.167487] -------------------------------------------- [15.167733] kworker/u8:3/146 is trying to acquire lock: [15.167733] ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: find_free_extent+0x15a/0x14f0 [btrfs] [15.167733] [15.167733] but task is already holding lock: [15.167733] ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_create_pending_block_groups+0x20a/0x560 [btrfs] [15.167733] [15.167733] other info that might help us debug this: [15.167733] Possible unsafe locking scenario: [15.167733] [15.171834] CPU0 [15.171834] ---- [15.171834] lock(&fs_devs->device_list_mutex); [15.171834] lock(&fs_devs->device_list_mutex); [15.171834] [15.171834] *** DEADLOCK *** [15.171834] [15.171834] May be due to missing lock nesting notation [15.171834] [15.171834] 5 locks held by kworker/u8:3/146: [15.171834] #0: ffff888100050938 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x1c3/0x5a0 [15.171834] jwrdegoede#1: ffffc9000067be80 ((work_completion)(&fs_info->async_data_reclaim_work)){+.+.}-{0:0}, at: process_one_work+0x1c3/0x5a0 [15.176244] jwrdegoede#2: ffff88810521e620 (sb_internal){.+.+}-{0:0}, at: flush_space+0x335/0x600 [btrfs] [15.176244] jwrdegoede#3: ffff888102962ee0 (&fs_devs->device_list_mutex){+.+.}-{3:3}, at: btrfs_create_pending_block_groups+0x20a/0x560 [btrfs] [15.176244] jwrdegoede#4: ffff8881152e4b78 (btrfs-dev-00){++++}-{3:3}, at: __btrfs_tree_lock+0x27/0x130 [btrfs] [15.179641] [15.179641] stack backtrace: [15.179641] CPU: 1 PID: 146 Comm: kworker/u8:3 Not tainted 5.17.0-rc6-dennis linux-sunxi#79 [15.179641] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1.fc35 04/01/2014 [15.179641] Workqueue: events_unbound btrfs_async_reclaim_data_space [btrfs] [15.179641] Call Trace: [15.179641] <TASK> [15.179641] dump_stack_lvl+0x45/0x59 [15.179641] __lock_acquire.cold+0x217/0x2b2 [15.179641] lock_acquire+0xbf/0x2b0 [15.183838] ? find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] __mutex_lock+0x8e/0x970 [15.183838] ? find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] ? find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] ? lock_is_held_type+0xd7/0x130 [15.183838] ? find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] find_free_extent+0x15a/0x14f0 [btrfs] [15.183838] ? _raw_spin_unlock+0x24/0x40 [15.183838] ? btrfs_get_alloc_profile+0x106/0x230 [btrfs] [15.187601] btrfs_reserve_extent+0x131/0x260 [btrfs] [15.187601] btrfs_alloc_tree_block+0xb5/0x3b0 [btrfs] [15.187601] __btrfs_cow_block+0x138/0x600 [btrfs] [15.187601] btrfs_cow_block+0x10f/0x230 [btrfs] [15.187601] btrfs_search_slot+0x55f/0xbc0 [btrfs] [15.187601] ? lock_is_held_type+0xd7/0x130 [15.187601] btrfs_insert_empty_items+0x2d/0x60 [btrfs] [15.187601] btrfs_create_pending_block_groups+0x2b3/0x560 [btrfs] [15.187601] __btrfs_end_transaction+0x36/0x2a0 [btrfs] [15.192037] flush_space+0x374/0x600 [btrfs] [15.192037] ? find_held_lock+0x2b/0x80 [15.192037] ? btrfs_async_reclaim_data_space+0x49/0x180 [btrfs] [15.192037] ? lock_release+0x131/0x2b0 [15.192037] btrfs_async_reclaim_data_space+0x70/0x180 [btrfs] [15.192037] process_one_work+0x24c/0x5a0 [15.192037] worker_thread+0x4a/0x3d0 Fixes: a85f05e ("btrfs: zoned: avoid chunk allocation if active block group has enough space") CC: stable@vger.kernel.org # 5.16+ Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Jun 10, 2022
[ Upstream commit 3fed9e5 ] If a compat process tries to execute an unknown system call above the __ARM_NR_COMPAT_END number, the kernel sends a SIGILL signal to the offending process. Information about the error is printed to dmesg in compat_arm_syscall() -> arm64_notify_die() -> arm64_force_sig_fault() -> arm64_show_signal(). arm64_show_signal() interprets a non-zero value for current->thread.fault_code as an exception syndrome and displays the message associated with the ESR_ELx.EC field (bits 31:26). current->thread.fault_code is set in compat_arm_syscall() -> arm64_notify_die() with the bad syscall number instead of a valid ESR_ELx value. This means that the ESR_ELx.EC field has the value that the user set for the syscall number and the kernel can end up printing bogus exception messages*. For example, for the syscall number 0x68000000, which evaluates to ESR_ELx.EC value of 0x1A (ESR_ELx_EC_FPAC) the kernel prints this error: [ 18.349161] syscall[300]: unhandled exception: ERET/ERETAA/ERETAB, ESR 0x68000000, Oops - bad compat syscall(2) in syscall[10000+50000] [ 18.350639] CPU: 2 PID: 300 Comm: syscall Not tainted 5.18.0-rc1 linux-sunxi#79 [ 18.351249] Hardware name: Pine64 RockPro64 v2.0 (DT) [..] which is misleading, as the bad compat syscall has nothing to do with pointer authentication. Stop arm64_show_signal() from printing exception syndrome information by having compat_arm_syscall() set the ESR_ELx value to 0, as it has no meaning for an invalid system call number. The example above now becomes: [ 19.935275] syscall[301]: unhandled exception: Oops - bad compat syscall(2) in syscall[10000+50000] [ 19.936124] CPU: 1 PID: 301 Comm: syscall Not tainted 5.18.0-rc1-00005-g7e08006d4102 linux-sunxi#80 [ 19.936894] Hardware name: Pine64 RockPro64 v2.0 (DT) [..] which although shows less information because the syscall number, wrongfully advertised as the ESR value, is missing, it is better than showing plainly wrong information. The syscall number can be easily obtained with strace. *A 32-bit value above or equal to 0x8000_0000 is interpreted as a negative integer in compat_arm_syscal() and the condition scno < __ARM_NR_COMPAT_END evaluates to true; the syscall will exit to userspace in this case with the ENOSYS error code instead of arm64_notify_die() being called. Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com> Reviewed-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20220425114444.368693-3-alexandru.elisei@arm.com Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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Jan 5, 2023
…einit_dcmds()' [ Upstream commit 683b972 ] This patch fixes a NULL pointer dereference bug in brcmfmac that occurs when ptr which is NULL pointer passed as an argument of strlcpy() in brcmf_c_preinit_dcmds(). This happens when the driver passes a firmware version string that does not contain a space " ", making strrchr() return a null pointer. This patch adds a null pointer check. Found by a modified version of syzkaller. KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] CPU: 0 PID: 1983 Comm: kworker/0:2 Not tainted 5.14.0+ linux-sunxi#79 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014 Workqueue: usb_hub_wq hub_event RIP: 0010:strlen+0x1a/0x90 Code: 23 ff ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 90 48 b8 00 00 00 00 00 fc ff df 48 89 fa 55 48 89 fd 48 c1 ea 03 53 48 83 ec 08 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 04 84 c0 75 48 80 7d 00 00 RSP: 0018:ffffc90002bfedd8 EFLAGS: 00010296 RAX: dffffc0000000000 RBX: 1ffff9200057fdc1 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000020 RDI: 0000000000000001 RBP: 0000000000000001 R08: 0000000000000039 R09: ffffed1023549801 R10: ffff88811aa4c007 R11: ffffed1023549800 R12: ffff88800bc68d6c R13: ffffc90002bfef08 R14: ffff88800bc6bc7c R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88811aa00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020546180 CR3: 0000000117ff1000 CR4: 0000000000750ef0 PKRU: 55555554 Call Trace: brcmf_c_preinit_dcmds+0x9f2/0xc40 ? brcmf_c_set_joinpref_default+0x100/0x100 ? rcu_read_lock_sched_held+0xa1/0xd0 ? rcu_read_lock_bh_held+0xb0/0xb0 ? lock_acquire+0x19d/0x4e0 ? find_held_lock+0x2d/0x110 ? brcmf_usb_deq+0x1a7/0x260 ? brcmf_usb_rx_fill_all+0x5a/0xf0 brcmf_attach+0x246/0xd40 ? wiphy_new_nm+0x1703/0x1dd0 ? kmemdup+0x43/0x50 brcmf_usb_probe+0x12de/0x1690 ? brcmf_usbdev_qinit.constprop.0+0x470/0x470 usb_probe_interface+0x2aa/0x760 ? usb_probe_device+0x250/0x250 really_probe+0x205/0xb70 ? driver_allows_async_probing+0x130/0x130 __driver_probe_device+0x311/0x4b0 ? driver_allows_async_probing+0x130/0x130 driver_probe_device+0x4e/0x150 __device_attach_driver+0x1cc/0x2a0 bus_for_each_drv+0x156/0x1d0 ? bus_rescan_devices+0x30/0x30 ? lockdep_hardirqs_on_prepare+0x273/0x3e0 ? trace_hardirqs_on+0x46/0x160 __device_attach+0x23f/0x3a0 ? device_bind_driver+0xd0/0xd0 ? kobject_uevent_env+0x287/0x14b0 bus_probe_device+0x1da/0x290 device_add+0xb7b/0x1eb0 ? wait_for_completion+0x290/0x290 ? __fw_devlink_link_to_suppliers+0x5a0/0x5a0 usb_set_configuration+0xf59/0x16f0 usb_generic_driver_probe+0x82/0xa0 usb_probe_device+0xbb/0x250 ? usb_suspend+0x590/0x590 really_probe+0x205/0xb70 ? driver_allows_async_probing+0x130/0x130 __driver_probe_device+0x311/0x4b0 ? usb_generic_driver_match+0x75/0x90 ? driver_allows_async_probing+0x130/0x130 driver_probe_device+0x4e/0x150 __device_attach_driver+0x1cc/0x2a0 bus_for_each_drv+0x156/0x1d0 ? bus_rescan_devices+0x30/0x30 ? _raw_spin_unlock_irqrestore+0x47/0x50 __device_attach+0x23f/0x3a0 ? device_bind_driver+0xd0/0xd0 ? kobject_uevent_env+0x287/0x14b0 bus_probe_device+0x1da/0x290 device_add+0xb7b/0x1eb0 ? __fw_devlink_link_to_suppliers+0x5a0/0x5a0 ? kfree+0x14a/0x6b0 ? __usb_get_extra_descriptor+0x116/0x160 usb_new_device.cold+0x49c/0x1029 ? hub_disconnect+0x450/0x450 ? rwlock_bug.part.0+0x90/0x90 ? _raw_spin_unlock_irq+0x24/0x30 ? lockdep_hardirqs_on_prepare+0x273/0x3e0 hub_event+0x248b/0x31c9 ? usb_port_suspend.cold+0x139/0x139 ? check_irq_usage+0x861/0xf20 ? drain_workqueue+0x280/0x360 ? lock_release+0x640/0x640 ? rcu_read_lock_sched_held+0xa1/0xd0 ? rcu_read_lock_bh_held+0xb0/0xb0 ? lockdep_hardirqs_on_prepare+0x273/0x3e0 process_one_work+0x92b/0x1460 ? pwq_dec_nr_in_flight+0x330/0x330 ? rwlock_bug.part.0+0x90/0x90 worker_thread+0x95/0xe00 ? __kthread_parkme+0x115/0x1e0 ? process_one_work+0x1460/0x1460 kthread+0x3a1/0x480 ? set_kthread_struct+0x120/0x120 ret_from_fork+0x1f/0x30 Modulesdd linked in: ---[ end trace c112c68924ddd800 ]--- RIP: 0010:strlen+0x1a/0x90 Code: 23 ff ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 90 48 b8 00 00 00 00 00 fc ff df 48 89 fa 55 48 89 fd 48 c1 ea 03 53 48 83 ec 08 <0f> b6 04 02 48 89 fa 83 e2 07 38 d0 7f 04 84 c0 75 48 80 7d 00 00 RSP: 0018:ffffc90002bfedd8 EFLAGS: 00010296 RAX: dffffc0000000000 RBX: 1ffff9200057fdc1 RCX: 0000000000000000 RDX: 0000000000000000 RSI: 0000000000000020 RDI: 0000000000000001 RBP: 0000000000000001 R08: 0000000000000039 R09: ffffed1023549801 R10: ffff88811aa4c007 R11: ffffed1023549800 R12: ffff88800bc68d6c R13: ffffc90002bfef08 R14: ffff88800bc6bc7c R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff88811aa00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020546180 CR3: 0000000117ff1000 CR4: 0000000000750ef0 PKRU: 55555554 Kernel panic - not syncing: Fatal exception Kernel Offset: disabled Reported-by: Dokyung Song <dokyungs@yonsei.ac.kr> Reported-by: Jisoo Jang <jisoo.jang@yonsei.ac.kr> Reported-by: Minsuk Kang <linuxlovemin@yonsei.ac.kr> Signed-off-by: Jisoo Jang <jisoo.jang@yonsei.ac.kr> Signed-off-by: Kalle Valo <kvalo@kernel.org> Link: https://lore.kernel.org/r/20221101183642.166450-1-jisoo.jang@yonsei.ac.kr Signed-off-by: Sasha Levin <sashal@kernel.org>
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Stripped couple commits from import-sun5i branch. This was only done for ease cherry-picking.
Notice this is currently my WIP branch, so atleast first commit is not from import-sun5i ;)
Notice also that some changes might not be even improvements.