From: Jens Axboe <axboe(a)kernel.dk> Snipped from commit 9ca9fb24d5febccea354089c41f96a8ad0d853f8 upstream. While reworking the poll hashing in the v6.0 kernel, we ended up grabbing the ctx->uring_lock in poll update/removal. This also fixed a bug with linked timeouts racing with timeout expiry and poll removal. Bring back just the locking fix for that. Reported-and-tested-by: Querijn Voet <querijnqyn(a)gmail.com> Signed-off-by: Jens Axboe <axboe(a)kernel.dk> Signed-off-by: Greg Kroah-Hartman <gregkh(a)linuxfoundation.org> --- io_uring/io_uring.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c index db1243dae5ca..841f013333db 100644 --- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -5822,6 +5822,8 @@ static int io_poll_update(struct io_kiocb *req, unsigned int issue_flags) struct io_kiocb *preq; int ret2, ret = 0; + io_ring_submit_lock(ctx, !(issue_flags & IO_URING_F_NONBLOCK)); + spin_lock(&ctx->completion_lock); preq = io_poll_find(ctx, req->poll_update.old_user_data, true); if (!preq || !io_poll_disarm(preq)) { @@ -5853,6 +5855,7 @@ static int io_poll_update(struct io_kiocb *req, unsigned int issue_flags) req_set_fail(req); /* complete update request, we're done with it */ io_req_complete(req, ret); + io_ring_submit_unlock(ctx, !(issue_flags & IO_URING_F_NONBLOCK)); return 0; } -- 2.25.1