4.9-stable review patch. If anyone has any objections, please let me know.
------------------
From: Johannes Thumshirn jthumshirn@suse.de
[ Upstream commit 0bc315381fe9ed9fb91db8b0e82171b645ac008f ]
zram can handle at most SECTORS_PER_PAGE sectors in a bio's bvec. When using the NVMe over Fabrics loopback target which potentially sends a huge bulk of pages attached to the bio's bvec this results in a kernel panic because of array out of bounds accesses in zram_decompress_page().
Signed-off-by: Johannes Thumshirn jthumshirn@suse.de Reviewed-by: Hannes Reinecke hare@suse.com Reviewed-by: Sergey Senozhatsky sergey.senozhatsky@gmail.com Signed-off-by: Jens Axboe axboe@fb.com Signed-off-by: Sasha Levin alexander.levin@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/block/zram/zram_drv.c | 2 ++ 1 file changed, 2 insertions(+)
--- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1286,6 +1286,8 @@ static int zram_add(void) blk_queue_io_min(zram->disk->queue, PAGE_SIZE); blk_queue_io_opt(zram->disk->queue, PAGE_SIZE); zram->disk->queue->limits.discard_granularity = PAGE_SIZE; + zram->disk->queue->limits.max_sectors = SECTORS_PER_PAGE; + zram->disk->queue->limits.chunk_sectors = 0; blk_queue_max_discard_sectors(zram->disk->queue, UINT_MAX); /* * zram_bio_discard() will clear all logical blocks if logical block