From 4ca82dabc9fbf7bc5322aa54d802cb3cb7b125c5 Mon Sep 17 00:00:00 2001 From: Minchan Kim Date: Thu, 13 Apr 2017 14:56:35 -0700 Subject: [PATCH] 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@kernel.org Signed-off-by: Minchan Kim Cc: Sergey Senozhatsky Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- 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 dceb5ed..03a7408 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -928,7 +928,7 @@ 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