Messages in this thread | | | Date | Wed, 18 Mar 2020 18:59:09 -0700 | From | Nathan Chancellor <> | Subject | Re: [PATCH v2] dynamic_debug: Use address-of operator on section symbols |
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On Wed, Feb 19, 2020 at 10:13:20PM -0700, Nathan Chancellor wrote: > Clang warns: > > ../lib/dynamic_debug.c:1034:24: warning: array comparison always > evaluates to false [-Wtautological-compare] > if (__start___verbose == __stop___verbose) { > ^ > 1 warning generated. > > 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). > > Link: https://github.com/ClangBuiltLinux/linux/issues/894 > Suggested-by: Nick Desaulniers <ndesaulniers@google.com> > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> > --- > v1 -> v2: https://lore.kernel.org/lkml/20200219045423.54190-5-natechancellor@gmail.com/ > > * No longer a series because there is no prerequisite patch. > * Use address-of operator instead of casting to unsigned long. > > lib/dynamic_debug.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c > index aae17d9522e5..8f199f403ab5 100644 > --- a/lib/dynamic_debug.c > +++ b/lib/dynamic_debug.c > @@ -1031,7 +1031,7 @@ static int __init dynamic_debug_init(void) > int n = 0, entries = 0, modct = 0; > int verbose_bytes = 0; > > - if (__start___verbose == __stop___verbose) { > + if (&__start___verbose == &__stop___verbose) { > pr_warn("_ddebug table is empty in a CONFIG_DYNAMIC_DEBUG build\n"); > return 1; > } > -- > 2.25.1 >
Gentle ping for review/acceptance.
Cheers, Nathan
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