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Fix sparse errors #37

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mpe opened this issue Mar 4, 2016 · 9 comments
Open

Fix sparse errors #37

mpe opened this issue Mar 4, 2016 · 9 comments
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easy Should be easy

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@mpe
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mpe commented Mar 4, 2016

Running sparse reports ~1000 errors related to powerpc. They are not all correct, but many are and should be fixed.

An up-to-date report (built from Linus' tree) is available here:

https://openpower.xyz/job/linux-build-master/lastSuccessfulBuild/artifact/linux/sparse.log.gz

@ajdlinux
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We should probably try to get @daxtens's IBM-internal-Jenkins sparse and cppcheck dashboard on to openpower.xyz at some point.

@daxtens
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daxtens commented May 18, 2016

It's really really simple - the script is in the job, not an external repo.
Whoever owns openpower.xyz is welcome to copy it and I'd be happy to help.

On Wed, May 18, 2016 at 10:15 AM, Andrew Donnellan <notifications@github.com

wrote:

We should probably try to get @daxtens https://github.com/daxtens's
IBM-internal-Jenkins sparse and cppcheck dashboard on to openpower.xyz at
some point.


You are receiving this because you were mentioned.
Reply to this email directly or view it on GitHub
https://github.com/linuxppc/linux/issues/37#issuecomment-219891441

@ajdlinux
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Ping @csmart

mpe referenced this issue in linuxppc/linux Oct 31, 2016
Commit 2518ac5 ("staging: wilc1000: Replace kthread with workqueue
for host interface") adds an unconditional destroy_workqueue() on the
wilc's "hif_workqueue" soon after its creation thereby rendering
it unusable. It then further attempts to queue work onto this
non-existing hif_worqueue and results in:

Unable to handle kernel NULL pointer dereference at virtual address 00000010
pgd = de478000
[00000010] *pgd=3eec0831, *pte=00000000, *ppte=00000000
Internal error: Oops: 17 [#1] ARM
Modules linked in: wilc1000_sdio(C) wilc1000(C)
CPU: 0 PID: 825 Comm: ifconfig Tainted: G         C      4.8.0-rc8+ torvalds#37
Hardware name: Atmel SAMA5
task: df56f800 task.stack: deeb0000
PC is at __queue_work+0x90/0x284
LR is at __queue_work+0x58/0x284
pc : [<c0126bb0>]    lr : [<c0126b78>]    psr: 600f0093
sp : deeb1aa0  ip : def22d78  fp : deea6000
r10: 00000000  r9 : c0a08150  r8 : c0a2f05
r7 : 00000001  r6 : dee9b600  r5 : def22d74  r4 : 00000000
r3 : 00000000  r2 : def22d74  r1 : 07ffffff  r0 : 00000000
Flags: nZCv  IRQs off  FIQs on  Mode SVC_32  ISA ARM  Segment none
...
[<c0127060>] (__queue_work) from [<c0127298>] (queue_work_on+0x34/0x40)
[<c0127298>] (queue_work_on) from [<bf0076b4>] (wilc_enqueue_cmd+0x54/0x64 [wilc1000])
[<bf0076b4>] (wilc_enqueue_cmd [wilc1000]) from [<bf0082b4>] (wilc_set_wfi_drv_handler+0x48/0x70 [wilc1000])
[<bf0082b4>] (wilc_set_wfi_drv_handler [wilc1000]) from [<bf00509c>] (wilc_mac_open+0x214/0x250 [wilc1000])
[<bf00509c>] (wilc_mac_open [wilc1000]) from [<c04fde98>] (__dev_open+0xb8/0x11c)
[<c04fde98>] (__dev_open) from [<c04fe128>] (__dev_change_flags+0x94/0x158)
[<c04fe128>] (__dev_change_flags) from [<c04fe204>] (dev_change_flags+0x18/0x48)
[<c04fe204>] (dev_change_flags) from [<c0557d5c>] (devinet_ioctl+0x6b4/0x788)
[<c0557d5c>] (devinet_ioctl) from [<c04e40a0>] (sock_ioctl+0x154/0x2cc)
[<c04e40a0>] (sock_ioctl) from [<c01b16e0>] (do_vfs_ioctl+0x9c/0x878)
[<c01b16e0>] (do_vfs_ioctl) from [<c01b1ef0>] (SyS_ioctl+0x34/0x5c)
[<c01b1ef0>] (SyS_ioctl) from [<c0107520>] (ret_fast_syscall+0x0/0x3c)
Code: e5932004 e1520006 01a04003 0affffff (e5943010)
---[ end trace b612328adaa6bf20 ]---

This fix removes the unnecessary call to destroy_workqueue() while opening
the device to avoid the above kernel panic. The deinit routine already
does a good job of terminating the workqueue when no longer needed.

Reported-by: Nicolas Ferre <Nicolas.Ferre@microchip.com>
Fixes: 2518ac5 ("staging: wilc1000: Replace kthread with workqueue for host interface")
Cc: stable@vger.kernel.org # 4.8+
Signed-off-by: Aditya Shankar <Aditya.Shankar@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mpe referenced this issue in linuxppc/linux Oct 31, 2016
Vince Waver reported the following bug:

  WARNING: CPU: 0 PID: 21338 at arch/x86/mm/fault.c:435 vmalloc_fault+0x58/0x1f0
  CPU: 0 PID: 21338 Comm: perf_fuzzer Not tainted 4.8.0+ torvalds#37
  Hardware name: Hewlett-Packard HP Compaq Pro 6305 SFF/1850, BIOS K06 v02.57 08/16/2013
  Call Trace:
   <NMI>  ? dump_stack+0x46/0x59
   ? __warn+0xd5/0xee
   ? vmalloc_fault+0x58/0x1f0
   ? __do_page_fault+0x6d/0x48e
   ? perf_log_throttle+0xa4/0xf4
   ? trace_page_fault+0x22/0x30
   ? __unwind_start+0x28/0x42
   ? perf_callchain_kernel+0x75/0xac
   ? get_perf_callchain+0x13a/0x1f0
   ? perf_callchain+0x6a/0x6c
   ? perf_prepare_sample+0x71/0x2eb
   ? perf_event_output_forward+0x1a/0x54
   ? __default_send_IPI_shortcut+0x10/0x2d
   ? __perf_event_overflow+0xfb/0x167
   ? x86_pmu_handle_irq+0x113/0x150
   ? native_read_msr+0x6/0x34
   ? perf_event_nmi_handler+0x22/0x39
   ? perf_ibs_nmi_handler+0x4a/0x51
   ? perf_event_nmi_handler+0x22/0x39
   ? nmi_handle+0x4d/0xf0
   ? perf_ibs_handle_irq+0x3d1/0x3d1
   ? default_do_nmi+0x3c/0xd5
   ? do_nmi+0x92/0x102
   ? end_repeat_nmi+0x1a/0x1e
   ? entry_SYSCALL_64_after_swapgs+0x12/0x4a
   ? entry_SYSCALL_64_after_swapgs+0x12/0x4a
   ? entry_SYSCALL_64_after_swapgs+0x12/0x4a
   <EOE> ^A4---[ end trace 632723104d47d31a ]---
  BUG: stack guard page was hit at ffffc90008500000 (stack is ffffc900084fc000..ffffc900084fffff)
  kernel stack overflow (page fault): 0000 [#1] SMP
  ...

The NMI hit in the entry code right after setting up the stack pointer
from 'cpu_current_top_of_stack', so the kernel stack was empty.  The
'guess' version of __unwind_start() attempted to dereference the "top of
stack" pointer, which is not actually *on* the stack.

Add a check in the guess unwinder to deal with an empty stack.  (The
frame pointer unwinder already has such a check.)

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Fixes: 7c7900f ("x86/unwind: Add new unwind interface and implementations")
Link: http://lkml.kernel.org/r/20161024133127.e5evgeebdbohnmpb@treble
Signed-off-by: Ingo Molnar <mingo@kernel.org>
mpe referenced this issue in linuxppc/linux Jul 13, 2017
Correct these checkpatch.pl errors:

|ERROR: space required before that '-' (ctx:OxO)
|torvalds#37: FILE: include/linux/bug.h:37:
|+#define BUILD_BUG_ON_ZERO(e) (sizeof(struct { int:-!!(e); }))

|ERROR: space required before that '-' (ctx:OxO)
|torvalds#38: FILE: include/linux/bug.h:38:
|+#define BUILD_BUG_ON_NULL(e) ((void *)sizeof(struct { int:-!!(e); }))

I decided to wrap the bitfield expressions that begin with minus signs
in parentheses rather than insert spaces before the minus signs.

Link: http://lkml.kernel.org/r/20170525120316.24473-5-abbotti@mev.co.uk
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Jakub Kicinski <jakub.kicinski@netronome.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
mpe referenced this issue in linuxppc/linux May 25, 2018
Trivial fix to remove the following sparse warnings:

  arch/powerpc/kernel/module_32.c:112:74: warning: Using plain integer as NULL pointer
  arch/powerpc/kernel/module_32.c:117:74: warning: Using plain integer as NULL pointer
  drivers/macintosh/via-pmu.c:1155:28: warning: Using plain integer as NULL pointer
  drivers/macintosh/via-pmu.c:1230:20: warning: Using plain integer as NULL pointer
  drivers/macintosh/via-pmu.c:1385:36: warning: Using plain integer as NULL pointer
  drivers/macintosh/via-pmu.c:1752:23: warning: Using plain integer as NULL pointer
  drivers/macintosh/via-pmu.c:2084:19: warning: Using plain integer as NULL pointer
  drivers/macintosh/via-pmu.c:2110:32: warning: Using plain integer as NULL pointer
  drivers/macintosh/via-pmu.c:2167:19: warning: Using plain integer as NULL pointer
  drivers/macintosh/via-pmu.c:2183:19: warning: Using plain integer as NULL pointer
  drivers/macintosh/via-pmu.c:277:20: warning: Using plain integer as NULL pointer
  arch/powerpc/platforms/powermac/setup.c:155:67: warning: Using plain integer as NULL pointer
  arch/powerpc/platforms/powermac/setup.c:247:27: warning: Using plain integer as NULL pointer
  arch/powerpc/platforms/powermac/setup.c:249:27: warning: Using plain integer as NULL pointer
  arch/powerpc/platforms/powermac/setup.c:252:37: warning: Using plain integer as NULL pointer
  arch/powerpc/mm/tlb_hash32.c:127:21: warning: Using plain integer as NULL pointer
  arch/powerpc/mm/tlb_hash32.c:148:21: warning: Using plain integer as NULL pointer
  arch/powerpc/mm/tlb_hash32.c:44:21: warning: Using plain integer as NULL pointer
  arch/powerpc/mm/tlb_hash32.c:57:21: warning: Using plain integer as NULL pointer
  arch/powerpc/mm/tlb_hash32.c:87:21: warning: Using plain integer as NULL pointer
  arch/powerpc/kernel/btext.c:160:31: warning: Using plain integer as NULL pointer
  arch/powerpc/kernel/btext.c:167:22: warning: Using plain integer as NULL pointer
  arch/powerpc/kernel/btext.c:274:21: warning: Using plain integer as NULL pointer
  arch/powerpc/kernel/btext.c:285:31: warning: Using plain integer as NULL pointer
  arch/powerpc/include/asm/hugetlb.h:204:16: warning: Using plain integer as NULL pointer
  arch/powerpc/mm/ppc_mmu_32.c:170:21: warning: Using plain integer as NULL pointer
  arch/powerpc/platforms/powermac/pci.c:1227:23: warning: Using plain integer as NULL pointer
  arch/powerpc/platforms/powermac/pci.c:65:24: warning: Using plain integer as NULL pointer

Also use `--fix` command line option from `script/checkpatch --strict` to
remove the following:

  CHECK: Comparison to NULL could be written "!dispDeviceBase"
  torvalds#72: FILE: arch/powerpc/kernel/btext.c:160:
  +	if (dispDeviceBase == NULL)

  CHECK: Comparison to NULL could be written "!vbase"
  torvalds#80: FILE: arch/powerpc/kernel/btext.c:167:
  +	if (vbase == NULL)

  CHECK: Comparison to NULL could be written "!base"
  torvalds#89: FILE: arch/powerpc/kernel/btext.c:274:
  +	if (base == NULL)

  CHECK: Comparison to NULL could be written "!dispDeviceBase"
  torvalds#98: FILE: arch/powerpc/kernel/btext.c:285:
  +	if (dispDeviceBase == NULL)

  CHECK: Comparison to NULL could be written "strstr"
  torvalds#117: FILE: arch/powerpc/kernel/module_32.c:117:
  +		if (strstr(secstrings + sechdrs[i].sh_name, ".debug") != NULL)

  CHECK: Comparison to NULL could be written "!Hash"
  torvalds#130: FILE: arch/powerpc/mm/ppc_mmu_32.c:170:
  +	if (Hash == NULL)

  CHECK: Comparison to NULL could be written "Hash"
  torvalds#143: FILE: arch/powerpc/mm/tlb_hash32.c:44:
  +	if (Hash != NULL) {

  CHECK: Comparison to NULL could be written "!Hash"
  torvalds#152: FILE: arch/powerpc/mm/tlb_hash32.c:57:
  +	if (Hash == NULL) {

  CHECK: Comparison to NULL could be written "!Hash"
  torvalds#161: FILE: arch/powerpc/mm/tlb_hash32.c:87:
  +	if (Hash == NULL) {

  CHECK: Comparison to NULL could be written "!Hash"
  torvalds#170: FILE: arch/powerpc/mm/tlb_hash32.c:127:
  +	if (Hash == NULL) {

  CHECK: Comparison to NULL could be written "!Hash"
  torvalds#179: FILE: arch/powerpc/mm/tlb_hash32.c:148:
  +	if (Hash == NULL) {

  ERROR: space required after that ';' (ctx:VxV)
  torvalds#192: FILE: arch/powerpc/platforms/powermac/pci.c:65:
  +	for (; node != NULL;node = node->sibling) {

  CHECK: Comparison to NULL could be written "node"
  torvalds#192: FILE: arch/powerpc/platforms/powermac/pci.c:65:
  +	for (; node != NULL;node = node->sibling) {

  CHECK: Comparison to NULL could be written "!region"
  torvalds#201: FILE: arch/powerpc/platforms/powermac/pci.c:1227:
  +	if (region == NULL)

  CHECK: Comparison to NULL could be written "of_get_property"
  torvalds#214: FILE: arch/powerpc/platforms/powermac/setup.c:155:
  +		if (of_get_property(np, "cache-unified", NULL) != NULL && dc) {

  CHECK: Comparison to NULL could be written "!np"
  torvalds#223: FILE: arch/powerpc/platforms/powermac/setup.c:247:
  +		if (np == NULL)

  CHECK: Comparison to NULL could be written "np"
  torvalds#226: FILE: arch/powerpc/platforms/powermac/setup.c:249:
  +		if (np != NULL) {

  CHECK: Comparison to NULL could be written "l2cr"
  torvalds#230: FILE: arch/powerpc/platforms/powermac/setup.c:252:
  +			if (l2cr != NULL) {

  CHECK: Comparison to NULL could be written "via"
  torvalds#243: FILE: drivers/macintosh/via-pmu.c:277:
  +	if (via != NULL)

  CHECK: Comparison to NULL could be written "current_req"
  torvalds#252: FILE: drivers/macintosh/via-pmu.c:1155:
  +	if (current_req != NULL) {

  CHECK: Comparison to NULL could be written "!req"
  torvalds#261: FILE: drivers/macintosh/via-pmu.c:1230:
  +	if (req == NULL || pmu_state != idle

  CHECK: Comparison to NULL could be written "!req"
  torvalds#270: FILE: drivers/macintosh/via-pmu.c:1385:
  +			if (req == NULL) {

  CHECK: Comparison to NULL could be written "!pp"
  torvalds#288: FILE: drivers/macintosh/via-pmu.c:2084:
  +	if (pp == NULL)

  CHECK: Comparison to NULL could be written "!pp"
  torvalds#297: FILE: drivers/macintosh/via-pmu.c:2110:
  +	if (count < 1 || pp == NULL)

  CHECK: Comparison to NULL could be written "!pp"
  torvalds#306: FILE: drivers/macintosh/via-pmu.c:2167:
  +	if (pp == NULL)

  CHECK: Comparison to NULL could be written "pp"
  torvalds#315: FILE: drivers/macintosh/via-pmu.c:2183:
  +	if (pp != NULL) {

Link: https://github.com/linuxppc/linux/issues/37
Signed-off-by: Mathieu Malaterre <malat@debian.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
@leitao
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leitao commented Sep 25, 2018

I would like to start looking at those, since I am also playing with smatch.

Regarding sparse, there are several warnings and 3 error. I will start to analyze the errors first and then the warnings.

These are the current errors (4.19-rc5):


arch/powerpc/kernel/prom_init.c:1138:36: error: cannot size expression

different type (originally declared at arch/powerpc/platforms/powernv/powernv.h:11) - different modifiers
/usr/lib/gcc/powerpc64le-linux-gnu/7/include/altivec.h:34:2: error: Use the "-maltivec" flag to enable PowerPC AltiVec support

The first error should be really easy to get fixed. I'll go ahead and send a patch.

@chleroy
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chleroy commented Sep 25, 2018

Have you noted that Mathieu @malaterre has also some patches to fix some of the sparse feedback, see above.

@leitao
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leitao commented Sep 25, 2018

hi @chleroy,

Yes, and I also saw they were not fully integrated into 4.19 yet, but, most of them are s/0/NULL, which are sparse warnings. I am starting with sparse errors which seem that they were not fixed by @malaterre.

@leitao
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leitao commented Oct 21, 2018

I also spent some time on this issue this weekend.

https://github.com/leitao/linux/tree/sparse

mpe referenced this issue in linuxppc/linux Nov 13, 2018
Increase kasan instrumented kernel stack size from 32k to 64k. Other
architectures seems to get away with just doubling kernel stack size under
kasan, but on s390 this appears to be not enough due to bigger frame size.
The particular pain point is kasan inlined checks (CONFIG_KASAN_INLINE
vs CONFIG_KASAN_OUTLINE). With inlined checks one particular case hitting
stack overflow is fs sync on xfs filesystem:

 #0 [9a0681e8]  704 bytes  check_usage at 34b1fc
 #1 [9a0684a8]  432 bytes  check_usage at 34c710
 #2 [9a068658]  1048 bytes  validate_chain at 35044a
 #3 [9a068a70]  312 bytes  __lock_acquire at 3559fe
 #4 [9a068ba8]  440 bytes  lock_acquire at 3576ee
 #5 [9a068d60]  104 bytes  _raw_spin_lock at 21b44e0
 torvalds#6 [9a068dc8]  1992 bytes  enqueue_entity at 2dbf72
 torvalds#7 [9a069590]  1496 bytes  enqueue_task_fair at 2df5f0
 torvalds#8 [9a069b68]  64 bytes  ttwu_do_activate at 28f438
 torvalds#9 [9a069ba8]  552 bytes  try_to_wake_up at 298c4c
 torvalds#10 [9a069dd0]  168 bytes  wake_up_worker at 23f97c
 torvalds#11 [9a069e78]  200 bytes  insert_work at 23fc2e
 torvalds#12 [9a069f40]  648 bytes  __queue_work at 2487c0
 torvalds#13 [9a06a1c8]  200 bytes  __queue_delayed_work at 24db28
 torvalds#14 [9a06a290]  248 bytes  mod_delayed_work_on at 24de84
 torvalds#15 [9a06a388]  24 bytes  kblockd_mod_delayed_work_on at 153e2a0
 torvalds#16 [9a06a3a0]  288 bytes  __blk_mq_delay_run_hw_queue at 158168c
 torvalds#17 [9a06a4c0]  192 bytes  blk_mq_run_hw_queue at 1581a3c
 torvalds#18 [9a06a580]  184 bytes  blk_mq_sched_insert_requests at 15a2192
 torvalds#19 [9a06a638]  1024 bytes  blk_mq_flush_plug_list at 1590f3a
 torvalds#20 [9a06aa38]  704 bytes  blk_flush_plug_list at 1555028
 torvalds#21 [9a06acf8]  320 bytes  schedule at 219e476
 torvalds#22 [9a06ae38]  760 bytes  schedule_timeout at 21b0aac
 torvalds#23 [9a06b130]  408 bytes  wait_for_common at 21a1706
 torvalds#24 [9a06b2c8]  360 bytes  xfs_buf_iowait at fa1540
 torvalds#25 [9a06b430]  256 bytes  __xfs_buf_submit at fadae6
 torvalds#26 [9a06b530]  264 bytes  xfs_buf_read_map at fae3f6
 torvalds#27 [9a06b638]  656 bytes  xfs_trans_read_buf_map at 10ac9a8
 torvalds#28 [9a06b8c8]  304 bytes  xfs_btree_kill_root at e72426
 torvalds#29 [9a06b9f8]  288 bytes  xfs_btree_lookup_get_block at e7bc5e
 torvalds#30 [9a06bb18]  624 bytes  xfs_btree_lookup at e7e1a6
 torvalds#31 [9a06bd88]  2664 bytes  xfs_alloc_ag_vextent_near at dfa070
 torvalds#32 [9a06c7f0]  144 bytes  xfs_alloc_ag_vextent at dff3ca
 torvalds#33 [9a06c880]  1128 bytes  xfs_alloc_vextent at e05fce
 torvalds#34 [9a06cce8]  584 bytes  xfs_bmap_btalloc at e58342
 torvalds#35 [9a06cf30]  1336 bytes  xfs_bmapi_write at e618de
 torvalds#36 [9a06d468]  776 bytes  xfs_iomap_write_allocate at ff678e
 torvalds#37 [9a06d770]  720 bytes  xfs_map_blocks at f82af8
 torvalds#38 [9a06da40]  928 bytes  xfs_writepage_map at f83cd6
 torvalds#39 [9a06dde0]  320 bytes  xfs_do_writepage at f85872
 torvalds#40 [9a06df20]  1320 bytes  write_cache_pages at 73dfe8
 torvalds#41 [9a06e448]  208 bytes  xfs_vm_writepages at f7f892
 torvalds#42 [9a06e518]  88 bytes  do_writepages at 73fe6a
 torvalds#43 [9a06e570]  872 bytes  __writeback_single_inode at a20cb6
 torvalds#44 [9a06e8d8]  664 bytes  writeback_sb_inodes at a23be2
 torvalds#45 [9a06eb70]  296 bytes  __writeback_inodes_wb at a242e0
 torvalds#46 [9a06ec98]  928 bytes  wb_writeback at a2500e
 torvalds#47 [9a06f038]  848 bytes  wb_do_writeback at a260ae
 torvalds#48 [9a06f388]  536 bytes  wb_workfn at a28228
 torvalds#49 [9a06f5a0]  1088 bytes  process_one_work at 24a234
 torvalds#50 [9a06f9e0]  1120 bytes  worker_thread at 24ba26
 torvalds#51 [9a06fe40]  104 bytes  kthread at 26545a
 #52 [9a06fea8]             kernel_thread_starter at 21b6b62

To be able to increase the stack size to 64k reuse LLILL instruction
in __switch_to function to load 64k - STACK_FRAME_OVERHEAD - __PT_SIZE
(65192) value as unsigned.

Reported-by: Benjamin Block <bblock@linux.ibm.com>
Reviewed-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Vasily Gorbik <gor@linux.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
mpe referenced this issue in linuxppc/linux Nov 20, 2018
We get the following warning:

[   47.926140] 32-bit node address hash set to 2010a0a
[   47.927202]
[   47.927433] ================================
[   47.928050] WARNING: inconsistent lock state
[   47.928661] 4.19.0+ torvalds#37 Tainted: G            E
[   47.929346] --------------------------------
[   47.929954] inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
[   47.930116] swapper/3/0 [HC0[0]:SC1[3]:HE1:SE0] takes:
[   47.930116] 00000000af8bc31e (&(&ht->lock)->rlock){+.?.}, at: rhashtable_walk_enter+0x36/0xb0
[   47.930116] {SOFTIRQ-ON-W} state was registered at:
[   47.930116]   _raw_spin_lock+0x29/0x60
[   47.930116]   rht_deferred_worker+0x556/0x810
[   47.930116]   process_one_work+0x1f5/0x540
[   47.930116]   worker_thread+0x64/0x3e0
[   47.930116]   kthread+0x112/0x150
[   47.930116]   ret_from_fork+0x3a/0x50
[   47.930116] irq event stamp: 14044
[   47.930116] hardirqs last  enabled at (14044): [<ffffffff9a07fbba>] __local_bh_enable_ip+0x7a/0xf0
[   47.938117] hardirqs last disabled at (14043): [<ffffffff9a07fb81>] __local_bh_enable_ip+0x41/0xf0
[   47.938117] softirqs last  enabled at (14028): [<ffffffff9a0803ee>] irq_enter+0x5e/0x60
[   47.938117] softirqs last disabled at (14029): [<ffffffff9a0804a5>] irq_exit+0xb5/0xc0
[   47.938117]
[   47.938117] other info that might help us debug this:
[   47.938117]  Possible unsafe locking scenario:
[   47.938117]
[   47.938117]        CPU0
[   47.938117]        ----
[   47.938117]   lock(&(&ht->lock)->rlock);
[   47.938117]   <Interrupt>
[   47.938117]     lock(&(&ht->lock)->rlock);
[   47.938117]
[   47.938117]  *** DEADLOCK ***
[   47.938117]
[   47.938117] 2 locks held by swapper/3/0:
[   47.938117]  #0: 0000000062c64f90 ((&d->timer)){+.-.}, at: call_timer_fn+0x5/0x280
[   47.938117]  #1: 00000000ee39619c (&(&d->lock)->rlock){+.-.}, at: tipc_disc_timeout+0xc8/0x540 [tipc]
[   47.938117]
[   47.938117] stack backtrace:
[   47.938117] CPU: 3 PID: 0 Comm: swapper/3 Tainted: G            E     4.19.0+ torvalds#37
[   47.938117] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   47.938117] Call Trace:
[   47.938117]  <IRQ>
[   47.938117]  dump_stack+0x5e/0x8b
[   47.938117]  print_usage_bug+0x1ed/0x1ff
[   47.938117]  mark_lock+0x5b5/0x630
[   47.938117]  __lock_acquire+0x4c0/0x18f0
[   47.938117]  ? lock_acquire+0xa6/0x180
[   47.938117]  lock_acquire+0xa6/0x180
[   47.938117]  ? rhashtable_walk_enter+0x36/0xb0
[   47.938117]  _raw_spin_lock+0x29/0x60
[   47.938117]  ? rhashtable_walk_enter+0x36/0xb0
[   47.938117]  rhashtable_walk_enter+0x36/0xb0
[   47.938117]  tipc_sk_reinit+0xb0/0x410 [tipc]
[   47.938117]  ? mark_held_locks+0x6f/0x90
[   47.938117]  ? __local_bh_enable_ip+0x7a/0xf0
[   47.938117]  ? lockdep_hardirqs_on+0x20/0x1a0
[   47.938117]  tipc_net_finalize+0xbf/0x180 [tipc]
[   47.938117]  tipc_disc_timeout+0x509/0x540 [tipc]
[   47.938117]  ? call_timer_fn+0x5/0x280
[   47.938117]  ? tipc_disc_msg_xmit.isra.19+0xa0/0xa0 [tipc]
[   47.938117]  ? tipc_disc_msg_xmit.isra.19+0xa0/0xa0 [tipc]
[   47.938117]  call_timer_fn+0xa1/0x280
[   47.938117]  ? tipc_disc_msg_xmit.isra.19+0xa0/0xa0 [tipc]
[   47.938117]  run_timer_softirq+0x1f2/0x4d0
[   47.938117]  __do_softirq+0xfc/0x413
[   47.938117]  irq_exit+0xb5/0xc0
[   47.938117]  smp_apic_timer_interrupt+0xac/0x210
[   47.938117]  apic_timer_interrupt+0xf/0x20
[   47.938117]  </IRQ>
[   47.938117] RIP: 0010:default_idle+0x1c/0x140
[   47.938117] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 41 54 55 53 65 8b 2d d8 2b 74 65 0f 1f 44 00 00 e8 c6 2c 8b ff fb f4 <65> 8b 2d c5 2b 74 65 0f 1f 44 00 00 5b 5d 41 5c c3 65 8b 05 b4 2b
[   47.938117] RSP: 0018:ffffaf6ac0207ec8 EFLAGS: 00000206 ORIG_RAX: ffffffffffffff13
[   47.938117] RAX: ffff8f5b3735e200 RBX: 0000000000000003 RCX: 0000000000000001
[   47.938117] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff8f5b3735e200
[   47.938117] RBP: 0000000000000003 R08: 0000000000000001 R09: 0000000000000000
[   47.938117] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
[   47.938117] R13: 0000000000000000 R14: ffff8f5b3735e200 R15: ffff8f5b3735e200
[   47.938117]  ? default_idle+0x1a/0x140
[   47.938117]  do_idle+0x1bc/0x280
[   47.938117]  cpu_startup_entry+0x19/0x20
[   47.938117]  start_secondary+0x187/0x1c0
[   47.938117]  secondary_startup_64+0xa4/0xb0

The reason seems to be that tipc_net_finalize()->tipc_sk_reinit() is
calling the function rhashtable_walk_enter() within a timer interrupt.
We fix this by executing tipc_net_finalize() in work queue context.

Acked-by: Ying Xue <ying.xue@windriver.com>
Signed-off-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
mpe referenced this issue in linuxppc/linux Dec 2, 2018
The bug is not easily reproducable, as it may occur very infrequently
(we had machines with 20minutes heavy downloading before it occurred)
However, on a virual machine (VMWare on Windows 10 host) it occurred
pretty frequently (1-2 seconds after a speedtest was started)

dev->tx_skb mab be freed via dev_kfree_skb_irq on a callback
before it is set.

This causes the following problems:
- double free of the skb or potential memory leak
- in dmesg: 'recvmsg bug' and 'recvmsg bug 2' and eventually
  general protection fault

Example dmesg output:
[  134.841986] ------------[ cut here ]------------
[  134.841987] recvmsg bug: copied 9C24A555 seq 9C24B557 rcvnxt 9C25A6B3 fl 0
[  134.841993] WARNING: CPU: 7 PID: 2629 at /build/linux-hwe-On9fm7/linux-hwe-4.15.0/net/ipv4/tcp.c:1865 tcp_recvmsg+0x44d/0xab0
[  134.841994] Modules linked in: ipheth(OE) kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd glue_helper cryptd vmw_balloon intel_rapl_perf joydev input_leds serio_raw vmw_vsock_vmci_transport vsock shpchp i2c_piix4 mac_hid binfmt_misc vmw_vmci parport_pc ppdev lp parport autofs4 vmw_pvscsi vmxnet3 hid_generic usbhid hid vmwgfx ttm drm_kms_helper syscopyarea sysfillrect mptspi mptscsih sysimgblt ahci psmouse fb_sys_fops pata_acpi mptbase libahci e1000 drm scsi_transport_spi
[  134.842046] CPU: 7 PID: 2629 Comm: python Tainted: G        W  OE    4.15.0-34-generic torvalds#37~16.04.1-Ubuntu
[  134.842046] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017
[  134.842048] RIP: 0010:tcp_recvmsg+0x44d/0xab0
[  134.842048] RSP: 0018:ffffa6630422bcc8 EFLAGS: 00010286
[  134.842049] RAX: 0000000000000000 RBX: ffff997616f4f200 RCX: 0000000000000006
[  134.842049] RDX: 0000000000000007 RSI: 0000000000000082 RDI: ffff9976257d6490
[  134.842050] RBP: ffffa6630422bd98 R08: 0000000000000001 R09: 000000000004bba4
[  134.842050] R10: 0000000001e00c6f R11: 000000000004bba4 R12: ffff99760dee3000
[  134.842051] R13: 0000000000000000 R14: ffff99760dee3514 R15: 0000000000000000
[  134.842051] FS:  00007fe332347700(0000) GS:ffff9976257c0000(0000) knlGS:0000000000000000
[  134.842052] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  134.842053] CR2: 0000000001e41000 CR3: 000000020e9b4006 CR4: 00000000003606e0
[  134.842055] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  134.842055] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  134.842057] Call Trace:
[  134.842060]  ? aa_sk_perm+0x53/0x1a0
[  134.842064]  inet_recvmsg+0x51/0xc0
[  134.842066]  sock_recvmsg+0x43/0x50
[  134.842070]  SYSC_recvfrom+0xe4/0x160
[  134.842072]  ? __schedule+0x3de/0x8b0
[  134.842075]  ? ktime_get_ts64+0x4c/0xf0
[  134.842079]  SyS_recvfrom+0xe/0x10
[  134.842082]  do_syscall_64+0x73/0x130
[  134.842086]  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[  134.842086] RIP: 0033:0x7fe331f5a81d
[  134.842088] RSP: 002b:00007ffe8da98398 EFLAGS: 00000246 ORIG_RAX: 000000000000002d
[  134.842090] RAX: ffffffffffffffda RBX: ffffffffffffffff RCX: 00007fe331f5a81d
[  134.842094] RDX: 00000000000003fb RSI: 0000000001e00874 RDI: 0000000000000003
[  134.842095] RBP: 00007fe32f642c70 R08: 0000000000000000 R09: 0000000000000000
[  134.842097] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe332347698
[  134.842099] R13: 0000000001b7e0a0 R14: 0000000001e00874 R15: 0000000000000000
[  134.842103] Code: 24 fd ff ff e9 cc fe ff ff 48 89 d8 41 8b 8c 24 10 05 00 00 44 8b 45 80 48 c7 c7 08 bd 59 8b 48 89 85 68 ff ff ff e8 b3 c4 7d ff <0f> 0b 48 8b 85 68 ff ff ff e9 e9 fe ff ff 41 8b 8c 24 10 05 00
[  134.842126] ---[ end trace b7138fc08c83147f ]---
[  134.842144] general protection fault: 0000 [#1] SMP PTI
[  134.842145] Modules linked in: ipheth(OE) kvm_intel kvm irqbypass crct10dif_pclmul crc32_pclmul ghash_clmulni_intel pcbc aesni_intel aes_x86_64 crypto_simd glue_helper cryptd vmw_balloon intel_rapl_perf joydev input_leds serio_raw vmw_vsock_vmci_transport vsock shpchp i2c_piix4 mac_hid binfmt_misc vmw_vmci parport_pc ppdev lp parport autofs4 vmw_pvscsi vmxnet3 hid_generic usbhid hid vmwgfx ttm drm_kms_helper syscopyarea sysfillrect mptspi mptscsih sysimgblt ahci psmouse fb_sys_fops pata_acpi mptbase libahci e1000 drm scsi_transport_spi
[  134.842161] CPU: 7 PID: 2629 Comm: python Tainted: G        W  OE    4.15.0-34-generic torvalds#37~16.04.1-Ubuntu
[  134.842162] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 05/19/2017
[  134.842164] RIP: 0010:tcp_close+0x2c6/0x440
[  134.842165] RSP: 0018:ffffa6630422bde8 EFLAGS: 00010202
[  134.842167] RAX: 0000000000000000 RBX: ffff99760dee3000 RCX: 0000000180400034
[  134.842168] RDX: 5c4afd407207a6c4 RSI: ffffe868495bd300 RDI: ffff997616f4f200
[  134.842169] RBP: ffffa6630422be08 R08: 0000000016f4d401 R09: 0000000180400034
[  134.842169] R10: ffffa6630422bd98 R11: 0000000000000000 R12: 000000000000600c
[  134.842170] R13: 0000000000000000 R14: ffff99760dee30c8 R15: ffff9975bd44fe00
[  134.842171] FS:  00007fe332347700(0000) GS:ffff9976257c0000(0000) knlGS:0000000000000000
[  134.842173] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  134.842174] CR2: 0000000001e41000 CR3: 000000020e9b4006 CR4: 00000000003606e0
[  134.842177] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  134.842178] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  134.842179] Call Trace:
[  134.842181]  inet_release+0x42/0x70
[  134.842183]  __sock_release+0x42/0xb0
[  134.842184]  sock_close+0x15/0x20
[  134.842187]  __fput+0xea/0x220
[  134.842189]  ____fput+0xe/0x10
[  134.842191]  task_work_run+0x8a/0xb0
[  134.842193]  exit_to_usermode_loop+0xc4/0xd0
[  134.842195]  do_syscall_64+0xf4/0x130
[  134.842197]  entry_SYSCALL_64_after_hwframe+0x3d/0xa2
[  134.842197] RIP: 0033:0x7fe331f5a560
[  134.842198] RSP: 002b:00007ffe8da982e8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003
[  134.842200] RAX: 0000000000000000 RBX: 00007fe32f642c70 RCX: 00007fe331f5a560
[  134.842201] RDX: 00000000008f5320 RSI: 0000000001cd4b50 RDI: 0000000000000003
[  134.842202] RBP: 00007fe32f6500f8 R08: 000000000000003c R09: 00000000009343c0
[  134.842203] R10: 0000000000000000 R11: 0000000000000246 R12: 00007fe32f6500d0
[  134.842204] R13: 00000000008f5320 R14: 00000000008f5320 R15: 0000000001cd4770
[  134.842205] Code: c8 00 00 00 45 31 e4 49 39 fe 75 4d eb 50 83 ab d8 00 00 00 01 48 8b 17 48 8b 47 08 48 c7 07 00 00 00 00 48 c7 47 08 00 00 00 00 <48> 89 42 08 48 89 10 0f b6 57 34 8b 47 2c 2b 47 28 83 e2 01 80
[  134.842226] RIP: tcp_close+0x2c6/0x440 RSP: ffffa6630422bde8
[  134.842227] ---[ end trace b7138fc08c831480 ]---

The proposed patch eliminates a potential racing condition.
Before, usb_submit_urb was called and _after_ that, the skb was attached
(dev->tx_skb). So, on a callback it was possible, however unlikely that the
skb was freed before it was set. That way (because dev->tx_skb was not set
to NULL after it was freed), it could happen that a skb from a earlier
transmission was freed a second time (and the skb we should have freed did
not get freed at all)

Now we free the skb directly in ipheth_tx(). It is not passed to the
callback anymore, eliminating the posibility of a double free of the same
skb. Depending on the retval of usb_submit_urb() we use dev_kfree_skb_any()
respectively dev_consume_skb_any() to free the skb.

Signed-off-by: Oliver Zweigle <Oliver.Zweigle@faro.com>
Signed-off-by: Bernd Eckstein <3ernd.Eckstein@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
mpe referenced this issue in linuxppc/linux Dec 28, 2018
Just another map, this time an BPF_MAP_TYPE_ARRAY, stating with
one bool per syscall, stating if it should be filtered or not.

So, with a pre-built augmented_raw_syscalls.o file, we use:

  # perf trace -e open*,augmented_raw_syscalls.o
     0.000 ( 0.016 ms): DNS Res~er torvalds#37/29652 openat(dfd: CWD, filename: /etc/hosts, flags: CLOEXEC                 ) = 138
   187.039 ( 0.048 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /etc/fstab, flags: CLOEXEC                 ) = 11
   187.348 ( 0.041 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /proc/self/mountinfo, flags: CLOEXEC       ) = 11
   188.793 ( 0.036 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /proc/self/mountinfo, flags: CLOEXEC       ) = 11
   189.803 ( 0.029 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /proc/self/mountinfo, flags: CLOEXEC       ) = 11
   190.774 ( 0.027 ms): gsd-housekeepi/2436 openat(dfd: CWD, filename: /proc/self/mountinfo, flags: CLOEXEC       ) = 11
   284.620 ( 0.149 ms): DataStorage/3076 openat(dfd: CWD, filename: /home/acme/.mozilla/firefox/ina67tev.default/SiteSecurityServiceState.txt, flags: CREAT|TRUNC|WRONLY, mode: IRUGO|IWUSR|IWGRP) = 167
  ^C#

What is it that this gsd-housekeeping thingy needs to open
/proc/self/mountinfo four times periodically? :-)

This map will be extended to tell per-syscall parameters, i.e. how many
bytes to copy per arg, using the function signature to get the types and
then the size of those types, via BTF.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: https://lkml.kernel.org/n/tip-cy222g9ucvnym3raqvxp0hpg@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
@mpe mpe transferred this issue from linuxppc/linux Jan 7, 2019
@mpe mpe added the easy Should be easy label Jan 7, 2019
@chleroy
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chleroy commented Mar 9, 2019

Note that with sparse 0.5.2, each use of min() or max() generates the following warning:

warning: expression using sizeof(void)

This is fixed in sparse 0.6.0

@mpe
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mpe commented Mar 13, 2019

cc @ajdlinux might be worth updating the version we use with snowpatch ^

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