Thread (3 messages) 3 messages, 2 authors, 2016-09-26

RE: [PATCH v2] raid6/test/test.c: bug fix: Specify aligned(alignment) attributes to the char arrays

From: Kammela, Gayatri <hidden>
Date: 2016-09-23 00:18:04
Also in: lkml

Hi all,
Sorry for the noise! I didn't mean to send the version2.

-----Original Message-----
From: Kammela, Gayatri 
Sent: Thursday, September 22, 2016 5:08 PM
To: linux-raid@vger.kernel.org; linux-kernel@vger.kernel.org
Cc: shli@kernel.org; Anvin, H Peter <redacted>; Shankar, Ravi V <redacted>; Yu, Fenghua <redacted>; Kammela, Gayatri <redacted>; H . Peter Anvin <hpa@zytor.com>; Yu, Yu-cheng <redacted>
Subject: [PATCH v2] raid6/test/test.c: bug fix: Specify aligned(alignment) attributes to the char arrays

Specifying the aligned attributes to the char recovi[PAGE_SIZE] and char recovi[PAGE_SIZE] arrays, so that all malloc memory is page boundary aligned.

Without these alignment attributes, the test causes a segfault in userspace when the NDISKS are changed to 4 from 16.

Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Yu-cheng Yu <redacted>
Signed-off-by: Gayatri Kammela <redacted>
---
 lib/raid6/test/test.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/lib/raid6/test/test.c b/lib/raid6/test/test.c index 3bebbabdb510..32a00f11ac50 100644
--- a/lib/raid6/test/test.c
+++ b/lib/raid6/test/test.c
@@ -21,12 +21,13 @@
 
 #define NDISKS		16	/* Including P and Q */
 
-const char raid6_empty_zero_page[PAGE_SIZE] __attribute__((aligned(256)));
+const char raid6_empty_zero_page[PAGE_SIZE] 
+__attribute__((aligned(PAGE_SIZE)));
 struct raid6_calls raid6_call;
 
 char *dataptrs[NDISKS];
 char data[NDISKS][PAGE_SIZE];
-char recovi[PAGE_SIZE], recovj[PAGE_SIZE];
+char recovi[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
+char recovj[PAGE_SIZE] __attribute__((aligned(PAGE_SIZE)));
 
 static void makedata(int start, int stop)  {
--
2.7.4
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