The patch titled
Subject: mm/kmemleak.c: annotate a data race in checksum
has been added to the -mm tree. Its filename is
mm-kmemleak-annotate-a-data-race-in-checksum.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/mm-kmemleak-annotate-a-data-race-in-checksum.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/mm-kmemleak-annotate-a-data-race-in-checksum.patch
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------------------------------------------------------
From: Qian Cai <cai@xxxxxx>
Subject: mm/kmemleak.c: annotate a data race in checksum
The value of object->pointer could be accessed concurrently as noticed by
KCSAN,
BUG: KCSAN: data-race in crc32_le_base / do_raw_spin_lock
write to 0xffffb0ea683a7d50 of 4 bytes by task 23575 on cpu 12:
do_raw_spin_lock+0x114/0x200
debug_spin_lock_after at kernel/locking/spinlock_debug.c:91
(inlined by) do_raw_spin_lock at kernel/locking/spinlock_debug.c:115
_raw_spin_lock+0x40/0x50
__handle_mm_fault+0xa9e/0xd00
handle_mm_fault+0xfc/0x2f0
do_page_fault+0x263/0x6f9
page_fault+0x34/0x40
read to 0xffffb0ea683a7d50 of 4 bytes by task 839 on cpu 60:
crc32_le_base+0x67/0x350
crc32_le_base+0x67/0x350:
crc32_body at lib/crc32.c:106
(inlined by) crc32_le_generic at lib/crc32.c:179
(inlined by) crc32_le at lib/crc32.c:197
kmemleak_scan+0x528/0xd90
update_checksum at mm/kmemleak.c:1172
(inlined by) kmemleak_scan at mm/kmemleak.c:1497
kmemleak_scan_thread+0xcc/0xfa
kthread+0x1e0/0x200
ret_from_fork+0x27/0x50
Reported by Kernel Concurrency Sanitizer on:
CPU: 60 PID: 839 Comm: kmemleak Tainted: G W L 5.5.0-next-20200210+ #3
Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019
crc32() will dereference object->pointer. If a shattered value was
returned due to a data race, it will be corrected in the next scan. Thus,
annotate it as an intentional data race using the data_race() macro.
Link: http://lkml.kernel.org/r/1581438245-24391-1-git-send-email-cai@xxxxxx
Signed-off-by: Qian Cai <cai@xxxxxx>
Acked-by: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/kmemleak.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)
--- a/mm/kmemleak.c~mm-kmemleak-annotate-a-data-race-in-checksum
+++ a/mm/kmemleak.c
@@ -1169,7 +1169,12 @@ static bool update_checksum(struct kmeml
u32 old_csum = object->checksum;
kasan_disable_current();
- object->checksum = crc32(0, (void *)object->pointer, object->size);
+ /*
+ * crc32() will dereference object->pointer. If an unstable value was
+ * returned due to a data race, it will be corrected in the next scan.
+ */
+ object->checksum = data_race(crc32(0, (void *)object->pointer,
+ object->size));
kasan_enable_current();
return object->checksum != old_csum;
_
Patches currently in -mm which might be from cai@xxxxxx are
mm-kmemleak-annotate-a-data-race-in-checksum.patch
mm-swapfile-fix-and-annotate-various-data-races.patch
mm-memcontrol-fix-a-data-race-in-scan-count.patch
mm-list_lru-fix-a-data-race-in-list_lru_count_one.patch
mm-mempool-fix-a-data-race-in-mempool_free.patch
mm-rmap-annotate-a-data-race-at-tlb_flush_batched.patch
mm-frontswap-mark-various-intentional-data-races.patch
mm-page_io-mark-various-intentional-data-races.patch
mm-swap_state-mark-various-intentional-data-races.patch
