[patch 102/166] kernel/extable.c: use address-of operator on section symbols

Andrew Morton
2020-04-07T03:09:29Z

From: Nathan Chancellor <natechancellor@gmail.com>
Subject: kernel/extable.c: use address-of operator on section symbols

Clang warns:

../kernel/extable.c:37:52: warning: array comparison always evaluates to
a constant [-Wtautological-compare]
if (main_extable_sort_needed && __stop___ex_table > __start___ex_table) {
^
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/892
Link: http://lkml.kernel.org/r/20200219202036.45702-1-natechancellor@gmail.com
Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
Suggested-by: Nick Desaulniers <ndesaulniers@google.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

kernel/extable.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

--- a/kernel/extable.c~kernel-extable-use-address-of-operator-on-section-symbols
+++ a/kernel/extable.c
@@ -34,7 +34,8 @@ u32 __initdata __visible main_extable_so
/* Sort the kernel's built-in exception table */
void __init sort_main_extable(void)
{
- if (main_extable_sort_needed && __stop___ex_table > __start___ex_table) {
+ if (main_extable_sort_needed &&
+ &__stop___ex_table > &__start___ex_table) {
pr_notice("Sorting __ex_table...\n");
sort_extable(__start___ex_table, __stop___ex_table);
}
_