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| author | Marco Elver | 2021-06-07 14:56:51 +0200 |
|---|---|---|
| committer | Paul E. McKenney | 2021-07-20 13:49:43 -0700 |
| commit | 49f72d5358dd3c0d28bcd2232c513000b15480f0 (patch) | |
| tree | b837c0732cc8aa274ad60738a818491c71faad9f /Documentation/dev-tools | |
| parent | 08cac6049412061e571fadadc3e23464dc46d0f2 (diff) | |
kcsan: Rework atomic.h into permissive.h
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 <elver@google.com>
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'Documentation/dev-tools')
| -rw-r--r-- | Documentation/dev-tools/kcsan.rst | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/Documentation/dev-tools/kcsan.rst b/Documentation/dev-tools/kcsan.rst index 69dc9c502ccc..7db43c7c09b8 100644 --- a/Documentation/dev-tools/kcsan.rst +++ b/Documentation/dev-tools/kcsan.rst @@ -127,6 +127,14 @@ Kconfig options: causes KCSAN to not report data races due to conflicts where the only plain accesses are aligned writes up to word size. +* ``CONFIG_KCSAN_PERMISSIVE``: Enable additional permissive rules to ignore + certain classes of common data races. Unlike the above, the rules are more + complex involving value-change patterns, access type, and address. This + option depends on ``CONFIG_KCSAN_REPORT_VALUE_CHANGE_ONLY=y``. For details + please see the ``kernel/kcsan/permissive.h``. Testers and maintainers that + only focus on reports from specific subsystems and not the whole kernel are + recommended to disable this option. + To use the strictest possible rules, select ``CONFIG_KCSAN_STRICT=y``, which configures KCSAN to follow the Linux-kernel memory consistency model (LKMM) as closely as possible. |