kernel.git/Documentation/dev-tools/kcsan.rst, branch linux-5.16.y

kcsan: Rework atomic.h into permissive.h

2021-07-20T20:49:43Z

Rework atomic.h into permissive.h to better reflect its purpose, and introduce kcsan_ignore_address() and kcsan_ignore_data_race(). Introduce CONFIG_KCSAN_PERMISSIVE and update the stub functions in preparation for subsequent changes. As before, developers who choose to use KCSAN in "strict" mode will see all data races and are not affected. Furthermore, by relying on the value-change filter logic for kcsan_ignore_data_race(), even if the permissive rules are enabled, the opt-outs in report.c:skip_report() override them (such as for RCU-related functions by default). The option CONFIG_KCSAN_PERMISSIVE is disabled by default, so that the documented default behaviour of KCSAN does not change. Instead, like CONFIG_KCSAN_IGNORE_ATOMICS, the option needs to be explicitly opted in. Signed-off-by: Marco Elver Acked-by: Mark Rutland Signed-off-by: Paul E. McKenney

kcsan: Introduce CONFIG_KCSAN_STRICT

2021-07-20T20:49:43Z

Add a simpler Kconfig variable to configure KCSAN's "strict" mode. This makes it simpler in documentation or messages to suggest just a single configuration option to select the strictest checking mode (vs. currently having to list several options). Signed-off-by: Marco Elver Acked-by: Mark Rutland Signed-off-by: Paul E. McKenney

kcsan: Use URL link for pointing access-marking.txt

2021-05-18T17:58:15Z

For consistency within kcsan.rst, use a URL link as the same as in section "Data Races". Acked-by: Marco Elver Signed-off-by: Akira Yokosawa Signed-off-by: Paul E. McKenney

kcsan: Document "value changed" line

2021-05-18T17:58:15Z

Update the example reports based on the latest reports generated by kcsan_test module, which now include the "value changed" line. Add a brief description of the "value changed" line. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: Add pointer to access-marking.txt to data_race() bullet

2021-05-18T17:58:14Z

This commit references tools/memory-model/Documentation/access-marking.txt in the bullet introducing data_race(). The access-marking.txt file gives advice on when data_race() should and should not be used. Suggested-by: Akira Yokosawa Signed-off-by: Paul E. McKenney

kcsan: Add missing license and copyright headers

2021-03-08T22:27:43Z

Adds missing license and/or copyright headers for KCSAN source files. Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney

kcsan: Re-add GCC as a supported compiler

2020-06-29T19:04:48Z

GCC version 11 recently implemented all requirements to correctly support KCSAN: 1. Correct no_sanitize-attribute inlining behaviour: https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=4089df8ef4a63126b0774c39b6638845244c20d2 2. --param=tsan-distinguish-volatile https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=ab2789ec507a94f1a75a6534bca51c7b39037ce0 3. --param=tsan-instrument-func-entry-exit https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=06712fc68dc9843d9af7c7ac10047f49d305ad76 Therefore, we can re-enable GCC for KCSAN, and document the new compiler requirements. Signed-off-by: Marco Elver Cc: Martin Liska Signed-off-by: Paul E. McKenney

kcsan: Remove __no_kcsan_or_inline

2020-06-15T12:10:08Z

There are no more user of this function attribute, also, with us now actively supporting '__no_kcsan inline' it doesn't make sense to have in any case. Signed-off-by: Peter Zijlstra (Intel)

kcsan: Update Documentation to change supported compilers

2020-06-11T18:04:02Z

Document change in required compiler version for KCSAN, and remove the now redundant note about __no_kcsan and inlining problems with older compilers. Signed-off-by: Marco Elver Signed-off-by: Borislav Petkov Signed-off-by: Thomas Gleixner Acked-by: Peter Zijlstra (Intel) Acked-by: Will Deacon Link: https://lkml.kernel.org/r/20200521142047.169334-8-elver@google.com

kcsan: Introduce scoped ASSERT_EXCLUSIVE macros

2020-04-14T00:18:13Z

Introduce ASSERT_EXCLUSIVE_*_SCOPED(), which provide an intuitive interface to use the scoped-access feature, without having to explicitly mark the start and end of the desired scope. Basing duration of the checks on scope avoids accidental misuse and resulting false positives, which may be hard to debug. See added comments for usage. The macros are implemented using __attribute__((__cleanup__(func))), which is supported by all compilers that currently support KCSAN. Suggested-by: Boqun Feng Suggested-by: Paul E. McKenney Signed-off-by: Marco Elver Signed-off-by: Paul E. McKenney