There is a race condition leading to a kernel crash from a null dereference when attemping to access fc->lock in fuse_uring_create_queue(). fc may be NULL in the case where another thread is creating the uring in fuse_uring_create() and has set fc->ring but has not yet set ring->fc when fuse_uring_create_queue() reads ring->fc. This fix sets fc->ring only after ring->fc has been set, which guarantees now that ring->fc is a proper pointer when any queues are created. Signed-off-by: Joanne Koong <joannelkoong@xxxxxxxxx> Fixes: 24fe962c86f5 ("fuse: {io-uring} Handle SQEs - register commands") --- fs/fuse/dev_uring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/fuse/dev_uring.c b/fs/fuse/dev_uring.c index ab8c26042aa8..618a413ef400 100644 --- a/fs/fuse/dev_uring.c +++ b/fs/fuse/dev_uring.c @@ -235,9 +235,9 @@ static struct fuse_ring *fuse_uring_create(struct fuse_conn *fc) init_waitqueue_head(&ring->stop_waitq); - fc->ring = ring; ring->nr_queues = nr_queues; ring->fc = fc; + fc->ring = ring; ring->max_payload_sz = max_payload_size; atomic_set(&ring->queue_refs, 0); -- 2.47.1