diff options
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/kcsan-checks.h | 40 |
1 files changed, 40 insertions, 0 deletions
diff --git a/include/linux/kcsan-checks.h b/include/linux/kcsan-checks.h index 5dcadc221026..cf6961794e9a 100644 --- a/include/linux/kcsan-checks.h +++ b/include/linux/kcsan-checks.h @@ -96,4 +96,44 @@ static inline void kcsan_check_access(const volatile void *ptr, size_t size, kcsan_check_access(ptr, size, KCSAN_ACCESS_ATOMIC | KCSAN_ACCESS_WRITE) #endif +/** + * ASSERT_EXCLUSIVE_WRITER - assert no other threads are writing @var + * + * Assert that there are no other threads writing @var; other readers are + * allowed. This assertion can be used to specify properties of concurrent code, + * where violation cannot be detected as a normal data race. + * + * For example, if a per-CPU variable is only meant to be written by a single + * CPU, but may be read from other CPUs; in this case, reads and writes must be + * marked properly, however, if an off-CPU WRITE_ONCE() races with the owning + * CPU's WRITE_ONCE(), would not constitute a data race but could be a harmful + * race condition. Using this macro allows specifying this property in the code + * and catch such bugs. + * + * @var variable to assert on + */ +#define ASSERT_EXCLUSIVE_WRITER(var) \ + __kcsan_check_access(&(var), sizeof(var), KCSAN_ACCESS_ASSERT) + +/** + * ASSERT_EXCLUSIVE_ACCESS - assert no other threads are accessing @var + * + * Assert that no other thread is accessing @var (no readers nor writers). This + * assertion can be used to specify properties of concurrent code, where + * violation cannot be detected as a normal data race. + * + * For example, in a reference-counting algorithm where exclusive access is + * expected after the refcount reaches 0. We can check that this property + * actually holds as follows: + * + * if (refcount_dec_and_test(&obj->refcnt)) { + * ASSERT_EXCLUSIVE_ACCESS(*obj); + * safely_dispose_of(obj); + * } + * + * @var variable to assert on + */ +#define ASSERT_EXCLUSIVE_ACCESS(var) \ + __kcsan_check_access(&(var), sizeof(var), KCSAN_ACCESS_WRITE | KCSAN_ACCESS_ASSERT) + #endif /* _LINUX_KCSAN_CHECKS_H */ |