From: Shigeru Yoshida syoshida@redhat.com
commit 8d12ec10292877751ee4463b11a63bd850bc09b5 upstream.
hctx->user_data is set to vq in virtblk_init_hctx(). However, vq is freed on suspend and reallocated on resume. So, hctx->user_data is invalid after resume, and it will cause use-after-free accessing which will result in the kernel crash something like below:
[ 22.428391] Call Trace: [ 22.428899] <TASK> [ 22.429339] virtqueue_add_split+0x3eb/0x620 [ 22.430035] ? __blk_mq_alloc_requests+0x17f/0x2d0 [ 22.430789] ? kvm_clock_get_cycles+0x14/0x30 [ 22.431496] virtqueue_add_sgs+0xad/0xd0 [ 22.432108] virtblk_add_req+0xe8/0x150 [ 22.432692] virtio_queue_rqs+0xeb/0x210 [ 22.433330] blk_mq_flush_plug_list+0x1b8/0x280 [ 22.434059] __blk_flush_plug+0xe1/0x140 [ 22.434853] blk_finish_plug+0x20/0x40 [ 22.435512] read_pages+0x20a/0x2e0 [ 22.436063] ? folio_add_lru+0x62/0xa0 [ 22.436652] page_cache_ra_unbounded+0x112/0x160 [ 22.437365] filemap_get_pages+0xe1/0x5b0 [ 22.437964] ? context_to_sid+0x70/0x100 [ 22.438580] ? sidtab_context_to_sid+0x32/0x400 [ 22.439979] filemap_read+0xcd/0x3d0 [ 22.440917] xfs_file_buffered_read+0x4a/0xc0 [ 22.441984] xfs_file_read_iter+0x65/0xd0 [ 22.442970] __kernel_read+0x160/0x2e0 [ 22.443921] bprm_execve+0x21b/0x640 [ 22.444809] do_execveat_common.isra.0+0x1a8/0x220 [ 22.446008] __x64_sys_execve+0x2d/0x40 [ 22.446920] do_syscall_64+0x37/0x90 [ 22.447773] entry_SYSCALL_64_after_hwframe+0x63/0xcd
This patch fixes this issue by getting vq from vblk, and removes virtblk_init_hctx().
Fixes: 4e0400525691 ("virtio-blk: support polling I/O") Cc: "Suwan Kim" suwan.kim027@gmail.com Signed-off-by: Shigeru Yoshida syoshida@redhat.com Message-Id: 20220810160948.959781-1-syoshida@redhat.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/block/virtio_blk.c | 24 ++++++++++-------------- 1 file changed, 10 insertions(+), 14 deletions(-)
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c index 6fc7850c2b0a..d756423e0059 100644 --- a/drivers/block/virtio_blk.c +++ b/drivers/block/virtio_blk.c @@ -101,6 +101,14 @@ static inline blk_status_t virtblk_result(struct virtblk_req *vbr) } }
+static inline struct virtio_blk_vq *get_virtio_blk_vq(struct blk_mq_hw_ctx *hctx) +{ + struct virtio_blk *vblk = hctx->queue->queuedata; + struct virtio_blk_vq *vq = &vblk->vqs[hctx->queue_num]; + + return vq; +} + static int virtblk_add_req(struct virtqueue *vq, struct virtblk_req *vbr) { struct scatterlist hdr, status, *sgs[3]; @@ -416,7 +424,7 @@ static void virtio_queue_rqs(struct request **rqlist) struct request *requeue_list = NULL;
rq_list_for_each_safe(rqlist, req, next) { - struct virtio_blk_vq *vq = req->mq_hctx->driver_data; + struct virtio_blk_vq *vq = get_virtio_blk_vq(req->mq_hctx); bool kick;
if (!virtblk_prep_rq_batch(req)) { @@ -837,7 +845,7 @@ static void virtblk_complete_batch(struct io_comp_batch *iob) static int virtblk_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob) { struct virtio_blk *vblk = hctx->queue->queuedata; - struct virtio_blk_vq *vq = hctx->driver_data; + struct virtio_blk_vq *vq = get_virtio_blk_vq(hctx); struct virtblk_req *vbr; unsigned long flags; unsigned int len; @@ -862,22 +870,10 @@ static int virtblk_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob) return found; }
-static int virtblk_init_hctx(struct blk_mq_hw_ctx *hctx, void *data, - unsigned int hctx_idx) -{ - struct virtio_blk *vblk = data; - struct virtio_blk_vq *vq = &vblk->vqs[hctx_idx]; - - WARN_ON(vblk->tag_set.tags[hctx_idx] != hctx->tags); - hctx->driver_data = vq; - return 0; -} - static const struct blk_mq_ops virtio_mq_ops = { .queue_rq = virtio_queue_rq, .queue_rqs = virtio_queue_rqs, .commit_rqs = virtio_commit_rqs, - .init_hctx = virtblk_init_hctx, .complete = virtblk_request_done, .map_queues = virtblk_map_queues, .poll = virtblk_poll,