diff options
| author | Mikulas Patocka <mpatocka@redhat.com> | 2022-08-26 16:17:08 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-08-26 19:30:25 +0300 |
| commit | 8238b4579866b7c1bb99883cfe102a43db5506ff (patch) | |
| tree | a61b3a10f1d6b53bc7c05b08b8b49bb84156ee2e /include/asm-generic/bitops/non-atomic.h | |
| parent | 4c612826bec1441214816827979b62f84a097e91 (diff) | |
| download | linux-8238b4579866b7c1bb99883cfe102a43db5506ff.tar.xz | |
wait_on_bit: add an acquire memory barrier
There are several places in the kernel where wait_on_bit is not followed
by a memory barrier (for example, in drivers/md/dm-bufio.c:new_read).
On architectures with weak memory ordering, it may happen that memory
accesses that follow wait_on_bit are reordered before wait_on_bit and
they may return invalid data.
Fix this class of bugs by introducing a new function "test_bit_acquire"
that works like test_bit, but has acquire memory ordering semantics.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Acked-by: Will Deacon <will@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/asm-generic/bitops/non-atomic.h')
| -rw-r--r-- | include/asm-generic/bitops/non-atomic.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/asm-generic/bitops/non-atomic.h b/include/asm-generic/bitops/non-atomic.h index 5c37ced343ae..71f8d54a5195 100644 --- a/include/asm-generic/bitops/non-atomic.h +++ b/include/asm-generic/bitops/non-atomic.h @@ -13,6 +13,7 @@ #define arch___test_and_change_bit generic___test_and_change_bit #define arch_test_bit generic_test_bit +#define arch_test_bit_acquire generic_test_bit_acquire #include <asm-generic/bitops/non-instrumented-non-atomic.h> |