diff options
| author | Marco Elver <elver@google.com> | 2024-05-02 16:12:17 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2024-05-07 11:39:50 -0700 |
| commit | 31f605a308e627f06e4e6ab77254473f1c90f0bf (patch) | |
| tree | 40f60c986dd9199d0c12cc967206130237cca3aa /include/linux/compiler_types.h | |
| parent | 39cd87c4eb2b893354f3b850f916353f2658ae6f (diff) | |
kcsan, compiler_types: Introduce __data_racy type qualifier
Based on the discussion at [1], it would be helpful to mark certain
variables as explicitly "data racy", which would result in KCSAN not
reporting data races involving any accesses on such variables. To do
that, introduce the __data_racy type qualifier:
struct foo {
...
int __data_racy bar;
...
};
In KCSAN-kernels, __data_racy turns into volatile, which KCSAN already
treats specially by considering them "marked". In non-KCSAN kernels the
type qualifier turns into no-op.
The generated code between KCSAN-instrumented kernels and non-KCSAN
kernels is already huge (inserted calls into runtime for every memory
access), so the extra generated code (if any) due to volatile for few
such __data_racy variables are unlikely to have measurable impact on
performance.
Link: https://lore.kernel.org/all/CAHk-=wi3iondeh_9V2g3Qz5oHTRjLsOpoy83hb58MVh=nRZe0A@mail.gmail.com/ [1]
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Marco Elver <elver@google.com>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'include/linux/compiler_types.h')
| -rw-r--r-- | include/linux/compiler_types.h | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h index 2abaa3a825a9..a38162a8590d 100644 --- a/include/linux/compiler_types.h +++ b/include/linux/compiler_types.h @@ -273,9 +273,16 @@ struct ftrace_likely_data { * disable all instrumentation. See Kconfig.kcsan where this is mandatory. */ # define __no_kcsan __no_sanitize_thread __disable_sanitizer_instrumentation +/* + * Type qualifier to mark variables where all data-racy accesses should be + * ignored by KCSAN. Note, the implementation simply marks these variables as + * volatile, since KCSAN will treat such accesses as "marked". + */ +# define __data_racy volatile # define __no_sanitize_or_inline __no_kcsan notrace __maybe_unused #else # define __no_kcsan +# define __data_racy #endif #ifndef __no_sanitize_or_inline |