Commit 95c094fc authored May 21, 2020 by Marco Elver Committed by Thomas Gleixner Jun 11, 2020

compiler.h: Avoid nested statement expression in data_race()



It appears that compilers have trouble with nested statement
expressions. Therefore, remove one level of statement expression nesting
from the data_race() macro. This will help avoiding potential problems
in the future as its usage increases.

Reported-by: Borislav Petkov <bp@suse.de>
Reported-by: Nathan Chancellor <natechancellor@gmail.com>
Signed-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>
Tested-by: Nick Desaulniers <ndesaulniers@google.com>
Link: https://lkml.kernel.org/r/20200520221712.GA21166@zn.tnic
Link: https://lkml.kernel.org/r/20200521142047.169334-10-elver@google.com

parent 44b97dcc

include/linux/compiler.h

+5 −5

Original line number	Diff line number	Diff line
		@@ -264,12 +264,12 @@ void ftrace_likely_update(struct ftrace_likely_data *f, int val,
		*/
		#define data_race(expr) \
		({ \
		__unqual_scalar_typeof(({ expr; })) __v = ({ \
		__kcsan_disable_current(); \
		({ \
		__unqual_scalar_typeof(({ expr; })) __v = ({ expr; }); \
		expr; \
		}); \
		__kcsan_enable_current(); \
		__v; \
		}); \
		})

		/*

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