From 02a4843618fb35f847cf8c31cd3893873aa0edde Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Wed, 13 Sep 2017 09:17:57 -0400 Subject: brd: fix overflow in __brd_direct_access The code in __brd_direct_access multiplies the pgoff variable by page size and divides it by 512. It can cause overflow on 32-bit architectures. The overflow happens if we create ramdisk larger than 4G and use it as a sparse device. This patch replaces multiplication and division with multiplication by the number of sectors per page. Reviewed-by: Dan Williams Signed-off-by: Mikulas Patocka Fixes: 1647b9b959c7 ("brd: add dax_operations support") Cc: stable@vger.kernel.org # 4.12+ Signed-off-by: Jens Axboe --- drivers/block/brd.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/block/brd.c') diff --git a/drivers/block/brd.c b/drivers/block/brd.c index bbd0d186cfc0..2d7178f7754e 100644 --- a/drivers/block/brd.c +++ b/drivers/block/brd.c @@ -342,7 +342,7 @@ static long __brd_direct_access(struct brd_device *brd, pgoff_t pgoff, if (!brd) return -ENODEV; - page = brd_insert_page(brd, PFN_PHYS(pgoff) / 512); + page = brd_insert_page(brd, (sector_t)pgoff << PAGE_SECTORS_SHIFT); if (!page) return -ENOSPC; *kaddr = page_address(page); -- cgit v1.2.3