lib/dynamic_debug.c: use address-of operator on section symbols

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).

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: Jason Baron <jbaron@akamai.com>
Link: https://github.com/ClangBuiltLinux/linux/issues/894
Link: http://lkml.kernel.org/r/20200220051320.10739-1-natechancellor@gmail.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index aae17d9522e5e0a8265daab1870b7cfeffb54b7e..8f199f403ab50656c4d91344932204bee6ac9d17 100644 (file)
--- 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;
        }