From: Nathan Chancellor natechancellor@gmail.com
stable inclusion from linux-4.19.149 commit afe001488e7e8e1108a2d9fcac3757713ffae503
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[ Upstream commit b0d14fc43d39203ae025f20ef4d5d25d9ccf4be1 ]
Clang warns:
mm/kmemleak.c:1955:28: warning: array comparison always evaluates to a constant [-Wtautological-compare] if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata) ^ mm/kmemleak.c:1955:60: warning: array comparison always evaluates to a constant [-Wtautological-compare] if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata)
These are not true arrays, they are linker defined symbols, which are just addresses. Using the address of operator silences the warning and does not change the resulting assembly with either clang/ld.lld or gcc/ld (tested with diff + objdump -Dr).
Suggested-by: Nick Desaulniers ndesaulniers@google.com Signed-off-by: Nathan Chancellor natechancellor@gmail.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Acked-by: Catalin Marinas catalin.marinas@arm.com Link: https://github.com/ClangBuiltLinux/linux/issues/895 Link: http://lkml.kernel.org/r/20200220051551.44000-1-natechancellor@gmail.com Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- mm/kmemleak.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/kmemleak.c b/mm/kmemleak.c index 5eeabece0c17..f54734abf946 100644 --- a/mm/kmemleak.c +++ b/mm/kmemleak.c @@ -2039,7 +2039,7 @@ void __init kmemleak_init(void) create_object((unsigned long)__bss_start, __bss_stop - __bss_start, KMEMLEAK_GREY, GFP_ATOMIC); /* only register .data..ro_after_init if not within .data */ - if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata) + if (&__start_ro_after_init < &_sdata || &__end_ro_after_init > &_edata) create_object((unsigned long)__start_ro_after_init, __end_ro_after_init - __start_ro_after_init, KMEMLEAK_GREY, GFP_ATOMIC);