virtio_blk incorrectly established -1U as the default for these queue_limits. Set these limits to sane default values to avoid crashing the kernel. But the virtio-blk protocol should probably be extended to allow proper stacking of the disk's limits from the host. This change fixes a crash that can occur if the max_sectors_kb is modified to even be half of virtio_blk's advertised max_hw_sectors_kb: # cat /sys/block/vdb/queue/max_sectors_kb 512 # cat /sys/block/vdb/queue/max_hw_sectors_kb 2147483647 # echo 1073741824 > /sys/block/vdb/queue/max_sectors_kb Attempting to mkfs.xfs against /dev/vdb will result in hitting fs/direct-io.c:dio_send_cur_page()'s BUG_ON. While fixing the blk_queue_max_hw_sectors(q, -1U) call it was immediately apparent that the blk_queue_max_segment_size(q, -1U) also should be fixed. Signed-off-by: Mike Snitzer <snitzer@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx --- drivers/block/virtio_blk.c | 9 ++++++--- 1 files changed, 6 insertions(+), 3 deletions(-) v2: revise header to simplify the scope of the problem explanation diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index c6a27d5..68efbdc 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -674,8 +674,11 @@ static int virtblk_probe(struct virtio_device *vdev) /* No need to bounce any requests */ blk_queue_bounce_limit(q, BLK_BOUNCE_ANY); - /* No real sector limit. */ - blk_queue_max_hw_sectors(q, -1U); + /* + * Limited by disk's max_hw_sectors in host, but + * without that info establish a sane default. + */ + blk_queue_max_hw_sectors(q, BLK_DEF_MAX_SECTORS); /* Host can optionally specify maximum segment size and number of * segments. */ @@ -684,7 +687,7 @@ static int virtblk_probe(struct virtio_device *vdev) if (!err) blk_queue_max_segment_size(q, v); else - blk_queue_max_segment_size(q, -1U); + blk_queue_max_segment_size(q, BLK_MAX_SEGMENT_SIZE); /* Host can optionally specify the block size of the device */ err = virtio_cread_feature(vdev, VIRTIO_BLK_F_BLK_SIZE, -- 1.7.4.4 -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
