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authorMikulas Patocka <mpatocka@redhat.com>2017-09-13 16:17:57 +0300
committerJens Axboe <axboe@kernel.dk>2017-09-25 17:56:05 +0300
commit02a4843618fb35f847cf8c31cd3893873aa0edde (patch)
tree07a8caec8d3ab5e68f42026f9bea8cad31a968ce
parent820bf5c419e4b85298e5c3001bd1b5be46d60765 (diff)
downloadlinux-02a4843618fb35f847cf8c31cd3893873aa0edde.tar.xz
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 <dan.j.williams@intel.com> Signed-off-by: Mikulas Patocka <mpatocka@redhat.com> Fixes: 1647b9b959c7 ("brd: add dax_operations support") Cc: stable@vger.kernel.org # 4.12+ Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--drivers/block/brd.c2
1 files changed, 1 insertions, 1 deletions
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);