[027/155] mm/kmemleak.c: use address-of operator on section symbols

Commit Message

Andrew Morton April 2, 2020, 4:04 a.m. UTC

From: Nathan Chancellor <[e-mail]>
Subject: mm/kmemleak.c: use address-of operator on section symbols

Clang warns:

../mm/kmemleak.c:1955:28: warning: array comparison always evaluates to a constant [-Wtautological-compare]
        if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata)
                                  ^
../mm/kmemleak.c:1955:60: warning: array comparison always evaluates to a constant [-Wtautological-compare]
        if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata)


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/895
Link: http://lkml.kernel.org/r/[e-mail]
Suggested-by: Nick Desaulniers <[e-mail]>
Signed-off-by: Nathan Chancellor <[e-mail]>
Acked-by: Catalin Marinas <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/kmemleak.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Patch

--- a/mm/kmemleak.c~mm-kmemleak-use-address-of-operator-on-section-symbols
+++ a/mm/kmemleak.c
@@ -1947,7 +1947,7 @@  void __init kmemleak_init(void)
 	create_object((unsigned long)__bss_start, __bss_stop - __bss_start,
 		      KMEMLEAK_GREY, GFP_ATOMIC);
 	/* only register .data..ro_after_init if not within .data */
-	if (__start_ro_after_init < _sdata || __end_ro_after_init > _edata)
+	if (&__start_ro_after_init < &_sdata || &__end_ro_after_init > &_edata)
 		create_object((unsigned long)__start_ro_after_init,
 			      __end_ro_after_init - __start_ro_after_init,
 			      KMEMLEAK_GREY, GFP_ATOMIC);