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 c9e1960fefc8e4bcc5afb8ed0ec66cbb125bc3d0..1ce2fa9dc5adc231395065c7faf907007d95be0a 100644 (file)
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -1015,7 +1015,7 @@ 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;
        }