sg2042: fix build error on x86 #10
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…ooping not available" This reverts commit e9572e9.
…ttm_device" This reverts commit f251c16.
…n ttm_device Currently TTM utilizes cached memory regardless of whether the device have full DMA coherency (can snoop CPU cache). Save the device's DMA coherency status in struct ttm_device, to allow further support of devices w/o snooping capability (the capability missing on at least one part of the transmission between the CPU and the device). Signed-off-by: Icenowy Zheng <uwu@icenowy.me> Link: https://lore.kernel.org/r/20240629052247.2653363-2-uwu@icenowy.me [ Han Gao: add conditional compilation for dma_coherent ] Signed-off-by: Han Gao <rabenda.cn@gmail.com>
…snooping not available As we can now acquire the presence of the full DMA coherency (snooping capability) from ttm_device, we can now map the CPU side memory as write-combined when cached is requested and snooping is not avilable. Signed-off-by: Icenowy Zheng <uwu@icenowy.me> Link: https://lore.kernel.org/r/20240629052247.2653363-3-uwu@icenowy.me [ Han Gao: add conditional compilation for dma coherent operations ] Signed-off-by: Han Gao <rabenda.cn@gmail.com>
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smc_lo_register_dmb() allocates DMB buffers with kzalloc(), which are later passed to get_page() in smc_rx_splice(). Since kmalloc memory is not page-backed, this triggers WARN_ON_ONCE() in get_page() and prevents holding a refcount on the buffer. This can lead to use-after-free if the memory is released before splice_to_pipe() completes. Use folio_alloc() instead, ensuring DMBs are page-backed and safe for get_page(). WARNING: CPU: 18 PID: 12152 at ./include/linux/mm.h:1330 smc_rx_splice+0xaf8/0xe20 [smc] CPU: 18 UID: 0 PID: 12152 Comm: smcapp Kdump: loaded Not tainted 6.17.0-rc3-11705-g9cf4672ecfee #10 NONE Hardware name: IBM 3931 A01 704 (z/VM 7.4.0) Krnl PSW : 0704e00180000000 000793161032696c (smc_rx_splice+0xafc/0xe20 [smc]) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 Krnl GPRS: 0000000000000000 001cee80007d3001 00077400000000f8 0000000000000005 0000000000000001 001cee80007d3006 0007740000001000 001c000000000000 000000009b0c99e0 0000000000001000 001c0000000000f8 001c000000000000 000003ffcc6f7c88 0007740003e98000 0007931600000005 000792969b2ff7b8 Krnl Code: 0007931610326960: af000000 mc 0,0 0007931610326964: a7f4ff43 brc 15,00079316103267ea #0007931610326968: af000000 mc 0,0 >000793161032696c: a7f4ff3f brc 15,00079316103267ea 0007931610326970: e320f1000004 lg %r2,256(%r15) 0007931610326976: c0e53fd1b5f5 brasl %r14,000793168fd5d560 000793161032697c: a7f4fbb5 brc 15,00079316103260e6 0007931610326980: b904002b lgr %r2,%r11 Call Trace: smc_rx_splice+0xafc/0xe20 [smc] smc_rx_splice+0x756/0xe20 [smc]) smc_rx_recvmsg+0xa74/0xe00 [smc] smc_splice_read+0x1ce/0x3b0 [smc] sock_splice_read+0xa2/0xf0 do_splice_read+0x198/0x240 splice_file_to_pipe+0x7e/0x110 do_splice+0x59e/0xde0 __do_splice+0x11a/0x2d0 __s390x_sys_splice+0x140/0x1f0 __do_syscall+0x122/0x280 system_call+0x6e/0x90 Last Breaking-Event-Address: smc_rx_splice+0x960/0xe20 [smc] ---[ end trace 0000000000000000 ]--- Fixes: f7a2207 ("net/smc: implement DMB-related operations of loopback-ism") Reviewed-by: Mahanta Jambigi <mjambigi@linux.ibm.com> Signed-off-by: Sidraya Jayagond <sidraya@linux.ibm.com> Link: https://patch.msgid.link/20250917184220.801066-1-sidraya@linux.ibm.com Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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Running sha224_kunit on a KMSAN-enabled kernel results in a crash in
kmsan_internal_set_shadow_origin():
BUG: unable to handle page fault for address: ffffbc3840291000
#PF: supervisor read access in kernel mode
#PF: error_code(0x0000) - not-present page
PGD 1810067 P4D 1810067 PUD 192d067 PMD 3c17067 PTE 0
Oops: 0000 [#1] SMP NOPTI
CPU: 0 UID: 0 PID: 81 Comm: kunit_try_catch Tainted: G N 6.17.0-rc3 #10 PREEMPT(voluntary)
Tainted: [N]=TEST
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
RIP: 0010:kmsan_internal_set_shadow_origin+0x91/0x100
[...]
Call Trace:
<TASK>
__msan_memset+0xee/0x1a0
sha224_final+0x9e/0x350
test_hash_buffer_overruns+0x46f/0x5f0
? kmsan_get_shadow_origin_ptr+0x46/0xa0
? __pfx_test_hash_buffer_overruns+0x10/0x10
kunit_try_run_case+0x198/0xa00
This occurs when memset() is called on a buffer that is not 4-byte aligned
and extends to the end of a guard page, i.e. the next page is unmapped.
The bug is that the loop at the end of kmsan_internal_set_shadow_origin()
accesses the wrong shadow memory bytes when the address is not 4-byte
aligned. Since each 4 bytes are associated with an origin, it rounds the
address and size so that it can access all the origins that contain the
buffer. However, when it checks the corresponding shadow bytes for a
particular origin, it incorrectly uses the original unrounded shadow
address. This results in reads from shadow memory beyond the end of the
buffer's shadow memory, which crashes when that memory is not mapped.
To fix this, correctly align the shadow address before accessing the 4
shadow bytes corresponding to each origin.
Link: https://lkml.kernel.org/r/20250911195858.394235-1-ebiggers@kernel.org
Fixes: 2ef3cec ("kmsan: do not wipe out origin when doing partial unpoisoning")
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Tested-by: Alexander Potapenko <glider@google.com>
Reviewed-by: Alexander Potapenko <glider@google.com>
Cc: Dmitriy Vyukov <dvyukov@google.com>
Cc: Marco Elver <elver@google.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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[ Upstream commit a35c04d ] smc_lo_register_dmb() allocates DMB buffers with kzalloc(), which are later passed to get_page() in smc_rx_splice(). Since kmalloc memory is not page-backed, this triggers WARN_ON_ONCE() in get_page() and prevents holding a refcount on the buffer. This can lead to use-after-free if the memory is released before splice_to_pipe() completes. Use folio_alloc() instead, ensuring DMBs are page-backed and safe for get_page(). WARNING: CPU: 18 PID: 12152 at ./include/linux/mm.h:1330 smc_rx_splice+0xaf8/0xe20 [smc] CPU: 18 UID: 0 PID: 12152 Comm: smcapp Kdump: loaded Not tainted 6.17.0-rc3-11705-g9cf4672ecfee #10 NONE Hardware name: IBM 3931 A01 704 (z/VM 7.4.0) Krnl PSW : 0704e00180000000 000793161032696c (smc_rx_splice+0xafc/0xe20 [smc]) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 Krnl GPRS: 0000000000000000 001cee80007d3001 00077400000000f8 0000000000000005 0000000000000001 001cee80007d3006 0007740000001000 001c000000000000 000000009b0c99e0 0000000000001000 001c0000000000f8 001c000000000000 000003ffcc6f7c88 0007740003e98000 0007931600000005 000792969b2ff7b8 Krnl Code: 0007931610326960: af000000 mc 0,0 0007931610326964: a7f4ff43 brc 15,00079316103267ea #0007931610326968: af000000 mc 0,0 >000793161032696c: a7f4ff3f brc 15,00079316103267ea 0007931610326970: e320f1000004 lg %r2,256(%r15) 0007931610326976: c0e53fd1b5f5 brasl %r14,000793168fd5d560 000793161032697c: a7f4fbb5 brc 15,00079316103260e6 0007931610326980: b904002b lgr %r2,%r11 Call Trace: smc_rx_splice+0xafc/0xe20 [smc] smc_rx_splice+0x756/0xe20 [smc]) smc_rx_recvmsg+0xa74/0xe00 [smc] smc_splice_read+0x1ce/0x3b0 [smc] sock_splice_read+0xa2/0xf0 do_splice_read+0x198/0x240 splice_file_to_pipe+0x7e/0x110 do_splice+0x59e/0xde0 __do_splice+0x11a/0x2d0 __s390x_sys_splice+0x140/0x1f0 __do_syscall+0x122/0x280 system_call+0x6e/0x90 Last Breaking-Event-Address: smc_rx_splice+0x960/0xe20 [smc] ---[ end trace 0000000000000000 ]--- Fixes: f7a2207 ("net/smc: implement DMB-related operations of loopback-ism") Reviewed-by: Mahanta Jambigi <mjambigi@linux.ibm.com> Signed-off-by: Sidraya Jayagond <sidraya@linux.ibm.com> Link: https://patch.msgid.link/20250917184220.801066-1-sidraya@linux.ibm.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 85e1ff6 upstream. Running sha224_kunit on a KMSAN-enabled kernel results in a crash in kmsan_internal_set_shadow_origin(): BUG: unable to handle page fault for address: ffffbc3840291000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1810067 P4D 1810067 PUD 192d067 PMD 3c17067 PTE 0 Oops: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 81 Comm: kunit_try_catch Tainted: G N 6.17.0-rc3 #10 PREEMPT(voluntary) Tainted: [N]=TEST Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 RIP: 0010:kmsan_internal_set_shadow_origin+0x91/0x100 [...] Call Trace: <TASK> __msan_memset+0xee/0x1a0 sha224_final+0x9e/0x350 test_hash_buffer_overruns+0x46f/0x5f0 ? kmsan_get_shadow_origin_ptr+0x46/0xa0 ? __pfx_test_hash_buffer_overruns+0x10/0x10 kunit_try_run_case+0x198/0xa00 This occurs when memset() is called on a buffer that is not 4-byte aligned and extends to the end of a guard page, i.e. the next page is unmapped. The bug is that the loop at the end of kmsan_internal_set_shadow_origin() accesses the wrong shadow memory bytes when the address is not 4-byte aligned. Since each 4 bytes are associated with an origin, it rounds the address and size so that it can access all the origins that contain the buffer. However, when it checks the corresponding shadow bytes for a particular origin, it incorrectly uses the original unrounded shadow address. This results in reads from shadow memory beyond the end of the buffer's shadow memory, which crashes when that memory is not mapped. To fix this, correctly align the shadow address before accessing the 4 shadow bytes corresponding to each origin. Link: https://lkml.kernel.org/r/20250911195858.394235-1-ebiggers@kernel.org Fixes: 2ef3cec ("kmsan: do not wipe out origin when doing partial unpoisoning") Signed-off-by: Eric Biggers <ebiggers@kernel.org> Tested-by: Alexander Potapenko <glider@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit a35c04d ] smc_lo_register_dmb() allocates DMB buffers with kzalloc(), which are later passed to get_page() in smc_rx_splice(). Since kmalloc memory is not page-backed, this triggers WARN_ON_ONCE() in get_page() and prevents holding a refcount on the buffer. This can lead to use-after-free if the memory is released before splice_to_pipe() completes. Use folio_alloc() instead, ensuring DMBs are page-backed and safe for get_page(). WARNING: CPU: 18 PID: 12152 at ./include/linux/mm.h:1330 smc_rx_splice+0xaf8/0xe20 [smc] CPU: 18 UID: 0 PID: 12152 Comm: smcapp Kdump: loaded Not tainted 6.17.0-rc3-11705-g9cf4672ecfee #10 NONE Hardware name: IBM 3931 A01 704 (z/VM 7.4.0) Krnl PSW : 0704e00180000000 000793161032696c (smc_rx_splice+0xafc/0xe20 [smc]) R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3 Krnl GPRS: 0000000000000000 001cee80007d3001 00077400000000f8 0000000000000005 0000000000000001 001cee80007d3006 0007740000001000 001c000000000000 000000009b0c99e0 0000000000001000 001c0000000000f8 001c000000000000 000003ffcc6f7c88 0007740003e98000 0007931600000005 000792969b2ff7b8 Krnl Code: 0007931610326960: af000000 mc 0,0 0007931610326964: a7f4ff43 brc 15,00079316103267ea #0007931610326968: af000000 mc 0,0 >000793161032696c: a7f4ff3f brc 15,00079316103267ea 0007931610326970: e320f1000004 lg %r2,256(%r15) 0007931610326976: c0e53fd1b5f5 brasl %r14,000793168fd5d560 000793161032697c: a7f4fbb5 brc 15,00079316103260e6 0007931610326980: b904002b lgr %r2,%r11 Call Trace: smc_rx_splice+0xafc/0xe20 [smc] smc_rx_splice+0x756/0xe20 [smc]) smc_rx_recvmsg+0xa74/0xe00 [smc] smc_splice_read+0x1ce/0x3b0 [smc] sock_splice_read+0xa2/0xf0 do_splice_read+0x198/0x240 splice_file_to_pipe+0x7e/0x110 do_splice+0x59e/0xde0 __do_splice+0x11a/0x2d0 __s390x_sys_splice+0x140/0x1f0 __do_syscall+0x122/0x280 system_call+0x6e/0x90 Last Breaking-Event-Address: smc_rx_splice+0x960/0xe20 [smc] ---[ end trace 0000000000000000 ]--- Fixes: f7a2207 ("net/smc: implement DMB-related operations of loopback-ism") Reviewed-by: Mahanta Jambigi <mjambigi@linux.ibm.com> Signed-off-by: Sidraya Jayagond <sidraya@linux.ibm.com> Link: https://patch.msgid.link/20250917184220.801066-1-sidraya@linux.ibm.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 85e1ff6 upstream. Running sha224_kunit on a KMSAN-enabled kernel results in a crash in kmsan_internal_set_shadow_origin(): BUG: unable to handle page fault for address: ffffbc3840291000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 1810067 P4D 1810067 PUD 192d067 PMD 3c17067 PTE 0 Oops: 0000 [#1] SMP NOPTI CPU: 0 UID: 0 PID: 81 Comm: kunit_try_catch Tainted: G N 6.17.0-rc3 #10 PREEMPT(voluntary) Tainted: [N]=TEST Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014 RIP: 0010:kmsan_internal_set_shadow_origin+0x91/0x100 [...] Call Trace: <TASK> __msan_memset+0xee/0x1a0 sha224_final+0x9e/0x350 test_hash_buffer_overruns+0x46f/0x5f0 ? kmsan_get_shadow_origin_ptr+0x46/0xa0 ? __pfx_test_hash_buffer_overruns+0x10/0x10 kunit_try_run_case+0x198/0xa00 This occurs when memset() is called on a buffer that is not 4-byte aligned and extends to the end of a guard page, i.e. the next page is unmapped. The bug is that the loop at the end of kmsan_internal_set_shadow_origin() accesses the wrong shadow memory bytes when the address is not 4-byte aligned. Since each 4 bytes are associated with an origin, it rounds the address and size so that it can access all the origins that contain the buffer. However, when it checks the corresponding shadow bytes for a particular origin, it incorrectly uses the original unrounded shadow address. This results in reads from shadow memory beyond the end of the buffer's shadow memory, which crashes when that memory is not mapped. To fix this, correctly align the shadow address before accessing the 4 shadow bytes corresponding to each origin. Link: https://lkml.kernel.org/r/20250911195858.394235-1-ebiggers@kernel.org Fixes: 2ef3cec ("kmsan: do not wipe out origin when doing partial unpoisoning") Signed-off-by: Eric Biggers <ebiggers@kernel.org> Tested-by: Alexander Potapenko <glider@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Marco Elver <elver@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 48918ca ] The test starts a workload and then opens events. If the events fail to open, for example because of perf_event_paranoid, the gopipe of the workload is leaked and the file descriptor leak check fails when the test exits. To avoid this cancel the workload when opening the events fails. Before: ``` $ perf test -vv 7 7: PERF_RECORD_* events & perf_sample fields: --- start --- test child forked, pid 1189568 Using CPUID GenuineIntel-6-B7-1 ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) config 0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/) disabled 1 ------------------------------------------------------------ sys_perf_event_open: pid 0 cpu -1 group_fd -1 flags 0x8 sys_perf_event_open failed, error -13 ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) config 0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/) disabled 1 exclude_kernel 1 ------------------------------------------------------------ sys_perf_event_open: pid 0 cpu -1 group_fd -1 flags 0x8 = 3 ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) config 0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/) disabled 1 ------------------------------------------------------------ sys_perf_event_open: pid 0 cpu -1 group_fd -1 flags 0x8 sys_perf_event_open failed, error -13 ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) config 0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/) disabled 1 exclude_kernel 1 ------------------------------------------------------------ sys_perf_event_open: pid 0 cpu -1 group_fd -1 flags 0x8 = 3 Attempt to add: software/cpu-clock/ ..after resolving event: software/config=0/ cpu-clock -> software/cpu-clock/ ------------------------------------------------------------ perf_event_attr: type 1 (PERF_TYPE_SOFTWARE) size 136 config 0x9 (PERF_COUNT_SW_DUMMY) sample_type IP|TID|TIME|CPU read_format ID|LOST disabled 1 inherit 1 mmap 1 comm 1 enable_on_exec 1 task 1 sample_id_all 1 mmap2 1 comm_exec 1 ksymbol 1 bpf_event 1 { wakeup_events, wakeup_watermark } 1 ------------------------------------------------------------ sys_perf_event_open: pid 1189569 cpu 0 group_fd -1 flags 0x8 sys_perf_event_open failed, error -13 perf_evlist__open: Permission denied ---- end(-2) ---- Leak of file descriptor 6 that opened: 'pipe:[14200347]' ---- unexpected signal (6) ---- iFailed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon #0 0x565358f6666e in child_test_sig_handler builtin-test.c:311 #1 0x7f29ce849df0 in __restore_rt libc_sigaction.c:0 #2 0x7f29ce89e95c in __pthread_kill_implementation pthread_kill.c:44 #3 0x7f29ce849cc2 in raise raise.c:27 #4 0x7f29ce8324ac in abort abort.c:81 #5 0x565358f662d4 in check_leaks builtin-test.c:226 #6 0x565358f6682e in run_test_child builtin-test.c:344 #7 0x565358ef7121 in start_command run-command.c:128 #8 0x565358f67273 in start_test builtin-test.c:545 #9 0x565358f6771d in __cmd_test builtin-test.c:647 #10 0x565358f682bd in cmd_test builtin-test.c:849 #11 0x565358ee5ded in run_builtin perf.c:349 #12 0x565358ee6085 in handle_internal_command perf.c:401 #13 0x565358ee61de in run_argv perf.c:448 #14 0x565358ee6527 in main perf.c:555 torvalds#15 0x7f29ce833ca8 in __libc_start_call_main libc_start_call_main.h:74 torvalds#16 0x7f29ce833d65 in __libc_start_main@@GLIBC_2.34 libc-start.c:128 torvalds#17 0x565358e391c1 in _start perf[851c1] 7: PERF_RECORD_* events & perf_sample fields : FAILED! ``` After: ``` $ perf test 7 7: PERF_RECORD_* events & perf_sample fields : Skip (permissions) ``` Fixes: 16d00fe ("perf tests: Move test__PERF_RECORD into separate object") Signed-off-by: Ian Rogers <irogers@google.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Athira Rajeev <atrajeev@linux.ibm.com> Cc: Chun-Tse Shao <ctshao@google.com> Cc: Howard Chu <howardchu95@gmail.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Clark <james.clark@linaro.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
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Oct 23, 2025
commit 0570327 upstream. Before disabling SR-IOV via config space accesses to the parent PF, sriov_disable() first removes the PCI devices representing the VFs. Since commit 9d16947 ("PCI: Add global pci_lock_rescan_remove()") such removal operations are serialized against concurrent remove and rescan using the pci_rescan_remove_lock. No such locking was ever added in sriov_disable() however. In particular when commit 18f9e9d ("PCI/IOV: Factor out sriov_add_vfs()") factored out the PCI device removal into sriov_del_vfs() there was still no locking around the pci_iov_remove_virtfn() calls. On s390 the lack of serialization in sriov_disable() may cause double remove and list corruption with the below (amended) trace being observed: PSW: 0704c00180000000 0000000c914e4b38 (klist_put+56) GPRS: 000003800313fb48 0000000000000000 0000000100000001 0000000000000001 00000000f9b520a8 0000000000000000 0000000000002fbd 00000000f4cc9480 0000000000000001 0000000000000000 0000000000000000 0000000180692828 00000000818e8000 000003800313fe2c 000003800313fb20 000003800313fad8 #0 [3800313fb20] device_del at c9158ad5c #1 [3800313fb88] pci_remove_bus_device at c915105ba #2 [3800313fbd0] pci_iov_remove_virtfn at c9152f198 #3 [3800313fc28] zpci_iov_remove_virtfn at c90fb67c0 #4 [3800313fc60] zpci_bus_remove_device at c90fb6104 #5 [3800313fca0] __zpci_event_availability at c90fb3dca #6 [3800313fd08] chsc_process_sei_nt0 at c918fe4a2 #7 [3800313fd60] crw_collect_info at c91905822 #8 [3800313fe10] kthread at c90feb390 #9 [3800313fe68] __ret_from_fork at c90f6aa64 #10 [3800313fe98] ret_from_fork at c9194f3f2. This is because in addition to sriov_disable() removing the VFs, the platform also generates hot-unplug events for the VFs. This being the reverse operation to the hotplug events generated by sriov_enable() and handled via pdev->no_vf_scan. And while the event processing takes pci_rescan_remove_lock and checks whether the struct pci_dev still exists, the lack of synchronization makes this checking racy. Other races may also be possible of course though given that this lack of locking persisted so long observable races seem very rare. Even on s390 the list corruption was only observed with certain devices since the platform events are only triggered by config accesses after the removal, so as long as the removal finished synchronously they would not race. Either way the locking is missing so fix this by adding it to the sriov_del_vfs() helper. Just like PCI rescan-remove, locking is also missing in sriov_add_vfs() including for the error case where pci_stop_and_remove_bus_device() is called without the PCI rescan-remove lock being held. Even in the non-error case, adding new PCI devices and buses should be serialized via the PCI rescan-remove lock. Add the necessary locking. Fixes: 18f9e9d ("PCI/IOV: Factor out sriov_add_vfs()") Signed-off-by: Niklas Schnelle <schnelle@linux.ibm.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: Benjamin Block <bblock@linux.ibm.com> Reviewed-by: Farhan Ali <alifm@linux.ibm.com> Reviewed-by: Julian Ruess <julianr@linux.ibm.com> Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20250826-pci_fix_sriov_disable-v1-1-2d0bc938f2a3@linux.ibm.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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