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| author | Ming Lei <ming.lei@redhat.com> | 2024-08-30 05:41:45 +0200 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2024-08-30 22:46:59 +0200 |
| commit | c9ea57c91f03bcad415e1a20113bdb2077bcf990 (patch) | |
| tree | 5865f68b6cbf4a769432fbcda17dde2fd229ece2 | |
| parent | Merge tag 'md-6.12-20240829' of https://git.kernel.org/pub/scm/linux/kernel/g... (diff) | |
| download | linux-c9ea57c91f03bcad415e1a20113bdb2077bcf990.tar.xz linux-c9ea57c91f03bcad415e1a20113bdb2077bcf990.zip | |
nbd: fix race between timeout and normal completion
If request timetout is handled by nbd_requeue_cmd(), normal completion
has to be stopped for avoiding to complete this requeued request, other
use-after-free can be triggered.
Fix the race by clearing NBD_CMD_INFLIGHT in nbd_requeue_cmd(), meantime
make sure that cmd->lock is grabbed for clearing the flag and the
requeue.
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Yu Kuai <yukuai3@huawei.com>
Fixes: 2895f1831e91 ("nbd: don't clear 'NBD_CMD_INFLIGHT' flag if request is not completed")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Yu Kuai <yukuai3@huawei.com>
Link: https://lore.kernel.org/r/20240830034145.1827742-1-ming.lei@redhat.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | drivers/block/nbd.c | 13 |
1 files changed, 12 insertions, 1 deletions
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index 5b1811b1ba5f..4d06472bf112 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -181,6 +181,17 @@ static void nbd_requeue_cmd(struct nbd_cmd *cmd) { struct request *req = blk_mq_rq_from_pdu(cmd); + lockdep_assert_held(&cmd->lock); + + /* + * Clear INFLIGHT flag so that this cmd won't be completed in + * normal completion path + * + * INFLIGHT flag will be set when the cmd is queued to nbd next + * time. + */ + __clear_bit(NBD_CMD_INFLIGHT, &cmd->flags); + if (!test_and_set_bit(NBD_CMD_REQUEUED, &cmd->flags)) blk_mq_requeue_request(req, true); } @@ -491,8 +502,8 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req) nbd_mark_nsock_dead(nbd, nsock, 1); mutex_unlock(&nsock->tx_lock); } - mutex_unlock(&cmd->lock); nbd_requeue_cmd(cmd); + mutex_unlock(&cmd->lock); nbd_config_put(nbd); return BLK_EH_DONE; } |