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From: Minchan Kim <minchan@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: <linux-kernel@vger.kernel.org>,
	Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
	<kernel-team@lge.com>, Minchan Kim <minchan@kernel.org>,
	<stable@vger.kernel.org>
Subject: [PATCH 1/3] zram: fix operator precedence to get offset
Date: Thu, 13 Apr 2017 09:17:00 +0900
Message-ID: <1492042622-12074-1-git-send-email-minchan@kernel.org> (raw)

In zram_rw_page, the logic to get offset is wrong by operator precedence
(i.e., "<<" is higher than "&"). With wrong offset, zram can corrupt the
user's data. This patch fixes it.

Fixes: 8c7f01025 ("zram: implement rw_page operation of zram")
Cc: stable@vger.kernel.org
Signed-off-by: Minchan Kim <minchan@kernel.org>
---
 drivers/block/zram/zram_drv.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 9e2199060040..83c38a123242 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -930,7 +930,7 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector,
 	}
 
 	index = sector >> SECTORS_PER_PAGE_SHIFT;
-	offset = sector & (SECTORS_PER_PAGE - 1) << SECTOR_SHIFT;
+	offset = (sector & (SECTORS_PER_PAGE - 1)) << SECTOR_SHIFT;
 
 	bv.bv_page = page;
 	bv.bv_len = PAGE_SIZE;
-- 
2.7.4

             reply index

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-04-13  0:17 Minchan Kim [this message]
2017-04-13  0:17 ` [PATCH 2/3] zram: do not use copy_page with non-page alinged address Minchan Kim
2017-04-14  5:41   ` Sergey Senozhatsky
2017-04-14 15:40     ` Minchan Kim
2017-04-17  1:48   ` Sergey Senozhatsky
2017-04-13  0:17 ` [PATCH 3/3] zsmalloc: expand class bit Minchan Kim
2017-04-14  5:07 ` [PATCH 1/3] zram: fix operator precedence to get offset Sergey Senozhatsky
2017-04-14 15:33   ` Minchan Kim
2017-04-17  1:21     ` Sergey Senozhatsky
2017-04-17  1:54       ` Sergey Senozhatsky
2017-04-17  2:14         ` Minchan Kim
2017-04-17 10:50           ` Sergey Senozhatsky
2017-04-17 10:53             ` Sergey Senozhatsky
2017-04-17 23:53             ` Minchan Kim
2017-04-18  1:53               ` Sergey Senozhatsky
2017-04-18  2:47                 ` Minchan Kim
2017-04-17  1:21 ` Sergey Senozhatsky

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