linux-kernel - [PATCH] mm: fix RODATA_TEST failure "rodata

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Date:   Thu, 21 Sep 2017 11:37:28 +0200 (CEST)
From:   Christophe Leroy <christophe.leroy@....fr>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Kees Cook <keescook@...omium.org>,
        Jinbum Park <jinb.park7@...il.com>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        linuxppc-dev@...ts.ozlabs.org
Subject: [PATCH] mm: fix RODATA_TEST failure "rodata_test: test data was not read only"

On powerpc, RODATA_TEST fails with message the following messages:

[    6.199505] Freeing unused kernel memory: 528K
[    6.203935] rodata_test: test data was not read only

This is because GCC allocates it to .data section:

c0695034 g     O .data	00000004 rodata_test_data

Since commit 056b9d8a76924 ("mm: remove rodata_test_data export,
add pr_fmt"), rodata_test_data is used only inside rodata_test.c
By declaring it static, it gets properly allocated into .rodata
section instead of .data:

c04df710 l     O .rodata	00000004 rodata_test_data

Signed-off-by: Christophe Leroy <christophe.leroy@....fr>
---
 mm/rodata_test.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/rodata_test.c b/mm/rodata_test.c
index 6bb4deb12e78..d908c8769b48 100644
--- a/mm/rodata_test.c
+++ b/mm/rodata_test.c
@@ -14,7 +14,7 @@
 #include <linux/uaccess.h>
 #include <asm/sections.h>
 
-const int rodata_test_data = 0xC3;
+static const int rodata_test_data = 0xC3;
 
 void rodata_test(void)
 {
-- 
2.13.3