From: Minchan Kim <minchan@xxxxxxxxxx>
Subject: zram: fix operator precedence to get offset
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")
Link: http://lkml.kernel.org/r/1492042622-12074-1-git-send-email-minchan@xxxxxxxxxx
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
Cc: Sergey Senozhatsky <sergey.senozhatsky@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/block/zram/zram_drv.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff -puN drivers/block/zram/zram_drv.c~zram-fix-operator-precedence-to-get-offset drivers/block/zram/zram_drv.c
--- a/drivers/block/zram/zram_drv.c~zram-fix-operator-precedence-to-get-offset
+++ a/drivers/block/zram/zram_drv.c
@@ -928,7 +928,7 @@ static int zram_rw_page(struct block_dev
}
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;
_