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

commit 8306b057a85ec07482da5d4b99d5c0b47af69be1 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 01591a7b151f21a0d1ef6799961ada7e16e0e899..4d61fa3c6ec925519f5d18ca7cc1782bbe4465ea 100644 (file)
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -984,7 +984,7 @@ 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;
        }