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Marco Elver authored
Clang (unlike GCC) removes reads before writes with matching addresses in the same basic block. This is an optimization for TSAN, since writes will always cause conflict if the preceding read would have. However, for KCSAN we cannot rely on this option, because we apply several special rules to writes, in particular when the KCSAN_ASSUME_PLAIN_WRITES_ATOMIC option is selected. To avoid missing potential data races, pass the -tsan-instrument-read-before-write option to Clang if it is available [1]. [1] https://github.com/llvm/llvm-project/commit/151ed6aa38a3ec6c01973b35f684586b6e1c0f7eSigned-off-by:
Marco Elver <elver@google.com> Signed-off-by:
Borislav Petkov <bp@suse.de> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Acked-by:
Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by:
Will Deacon <will@kernel.org> Link: https://lkml.kernel.org/r/20200521142047.169334-5-elver@google.com
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