diff options
| author | Ingo Molnar <mingo@kernel.org> | 2019-11-19 19:54:39 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2019-11-19 19:56:28 +0100 |
| commit | 8e1d58ae0c8d4af9ab0141f7e8a9ca95720df01c (patch) | |
| tree | 7b09138ee1aca2825f86f5534bfd2caad83190ec /arch/x86/include/asm/bitops.h | |
| parent | af42d3466bdc8f39806b26f593604fdc54140bcb (diff) | |
| parent | 40d04110f87940b6a03bf0aa19cd29e84f465f20 (diff) | |
Merge branch 'for-mingo' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into locking/kcsan
Pull the KCSAN subsystem from Paul E. McKenney:
"This pull request contains base kernel concurrency sanitizer
(KCSAN) enablement for x86, courtesy of Marco Elver. KCSAN is a
sampling watchpoint-based data-race detector, and is documented in
Documentation/dev-tools/kcsan.rst. KCSAN was announced in September,
and much feedback has since been incorporated:
http://lkml.kernel.org/r/CANpmjNPJ_bHjfLZCAPV23AXFfiPiyXXqqu72n6TgWzb2Gnu1eA@mail.gmail.com
The data races located thus far have resulted in a number of fixes:
https://github.com/google/ktsan/wiki/KCSAN#upstream-fixes-of-data-races-found-by-kcsan
Additional information may be found here:
https://lore.kernel.org/lkml/20191114180303.66955-1-elver@google.com/
"
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/include/asm/bitops.h')
| -rw-r--r-- | arch/x86/include/asm/bitops.h | 6 |
1 files changed, 5 insertions, 1 deletions
diff --git a/arch/x86/include/asm/bitops.h b/arch/x86/include/asm/bitops.h index 7d1f6a49bfae..542b63ddc8aa 100644 --- a/arch/x86/include/asm/bitops.h +++ b/arch/x86/include/asm/bitops.h @@ -201,8 +201,12 @@ arch_test_and_change_bit(long nr, volatile unsigned long *addr) return GEN_BINARY_RMWcc(LOCK_PREFIX __ASM_SIZE(btc), *addr, c, "Ir", nr); } -static __always_inline bool constant_test_bit(long nr, const volatile unsigned long *addr) +static __no_kcsan_or_inline bool constant_test_bit(long nr, const volatile unsigned long *addr) { + /* + * Because this is a plain access, we need to disable KCSAN here to + * avoid double instrumentation via instrumented bitops. + */ return ((1UL << (nr & (BITS_PER_LONG-1))) & (addr[nr >> _BITOPS_LONG_SHIFT])) != 0; } |