linux-kernel - [PATCH v2] mm: kmemleak: Use address-of operator on section symbols

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Date:   Wed, 19 Feb 2020 22:15:51 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Catalin Marinas <catalin.marinas@....com>,
        Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        clang-built-linux@...glegroups.com,
        Nathan Chancellor <natechancellor@...il.com>,
        Nick Desaulniers <ndesaulniers@...gle.com>
Subject: [PATCH v2] mm: kmemleak: Use address-of operator on section symbols

Clang warns:

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
Suggested-by: Nick Desaulniers <ndesaulniers@...gle.com>
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
---

v1 -> v2: https://lore.kernel.org/lkml/20200219045423.54190-6-natechancellor@gmail.com/

* No longer a series because there is no prerequisite patch.
* Use address-of operator instead of casting to unsigned long.

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

diff --git a/mm/kmemleak.c b/mm/kmemleak.c
index aa6832432d6a..788dc5509539 100644
--- a/mm/kmemleak.c
+++ b/mm/kmemleak.c
@@ -1952,7 +1952,7 @@ 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);
-- 
2.25.1