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 fec610703095f994b10b1f9f8d909b5410fdcbfe..d56a78beb2794f4b9cc4737cd62f593402549ae0 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;
        }