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| author | Marco Elver <elver@google.com> | 2021-08-05 14:57:45 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-12-09 16:42:26 -0800 |
| commit | 69562e4983d93e2791c0bf128b07462afbd7f4dc (patch) | |
| tree | 3f09f093f4aea94918bd1ebb127f61a6f263d15d /scripts | |
| parent | 9756f64c8f2d19c0029a5827bda8ac275302ec22 (diff) | |
| download | linux-69562e4983d93e2791c0bf128b07462afbd7f4dc.tar.bz2 | |
kcsan: Add core support for a subset of weak memory modeling
Add support for modeling a subset of weak memory, which will enable
detection of a subset of data races due to missing memory barriers.
KCSAN's approach to detecting missing memory barriers is based on
modeling access reordering, and enabled if `CONFIG_KCSAN_WEAK_MEMORY=y`,
which depends on `CONFIG_KCSAN_STRICT=y`. The feature can be enabled or
disabled at boot and runtime via the `kcsan.weak_memory` boot parameter.
Each memory access for which a watchpoint is set up, is also selected
for simulated reordering within the scope of its function (at most 1
in-flight access).
We are limited to modeling the effects of "buffering" (delaying the
access), since the runtime cannot "prefetch" accesses (therefore no
acquire modeling). Once an access has been selected for reordering, it
is checked along every other access until the end of the function scope.
If an appropriate memory barrier is encountered, the access will no
longer be considered for reordering.
When the result of a memory operation should be ordered by a barrier,
KCSAN can then detect data races where the conflict only occurs as a
result of a missing barrier due to reordering accesses.
Suggested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Marco Elver <elver@google.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'scripts')
| -rw-r--r-- | scripts/Makefile.kcsan | 9 |
1 files changed, 7 insertions, 2 deletions
diff --git a/scripts/Makefile.kcsan b/scripts/Makefile.kcsan index 37cb504c77e1..4c7f0d282e42 100644 --- a/scripts/Makefile.kcsan +++ b/scripts/Makefile.kcsan @@ -9,7 +9,12 @@ endif # Keep most options here optional, to allow enabling more compilers if absence # of some options does not break KCSAN nor causes false positive reports. -export CFLAGS_KCSAN := -fsanitize=thread \ - $(call cc-option,$(call cc-param,tsan-instrument-func-entry-exit=0) -fno-optimize-sibling-calls) \ +kcsan-cflags := -fsanitize=thread -fno-optimize-sibling-calls \ $(call cc-option,$(call cc-param,tsan-compound-read-before-write=1),$(call cc-option,$(call cc-param,tsan-instrument-read-before-write=1))) \ $(call cc-param,tsan-distinguish-volatile=1) + +ifndef CONFIG_KCSAN_WEAK_MEMORY +kcsan-cflags += $(call cc-option,$(call cc-param,tsan-instrument-func-entry-exit=0)) +endif + +export CFLAGS_KCSAN := $(kcsan-cflags) |