From 24f473769e7ecf35e2772469a063d5a8bbca6f63 Mon Sep 17 00:00:00 2001 From: Jens Axboe Date: Sat, 17 Jun 2023 19:50:24 -0600 Subject: [PATCH] io_uring/poll: serialize poll linked timer start with poll removal Commit ef7dfac51d8ed961b742218f526bd589f3900a59 upstream. We selectively grab the ctx->uring_lock for poll update/removal, but we really should grab it from the start to fully synchronize with linked timeouts. Normally this is indeed the case, but if requests are forced async by the application, we don't fully cover removal and timer disarm within the uring_lock. Make this simpler by having consistent locking state for poll removal. Cc: stable@vger.kernel.org # 6.1+ Reported-by: Querijn Voet Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman --- io_uring/poll.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-) diff --git a/io_uring/poll.c b/io_uring/poll.c index 4788073ec45d..869e1d2a4413 100644 --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -993,8 +993,9 @@ int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags) struct io_hash_bucket *bucket; struct io_kiocb *preq; int ret2, ret = 0; - bool locked; + bool locked = true; + io_ring_submit_lock(ctx, issue_flags); preq = io_poll_find(ctx, true, &cd, &ctx->cancel_table, &bucket); ret2 = io_poll_disarm(preq); if (bucket) @@ -1006,12 +1007,10 @@ int io_poll_remove(struct io_kiocb *req, unsigned int issue_flags) goto out; } - io_ring_submit_lock(ctx, issue_flags); preq = io_poll_find(ctx, true, &cd, &ctx->cancel_table_locked, &bucket); ret2 = io_poll_disarm(preq); if (bucket) spin_unlock(&bucket->lock); - io_ring_submit_unlock(ctx, issue_flags); if (ret2) { ret = ret2; goto out; @@ -1035,7 +1034,7 @@ found: if (poll_update->update_user_data) preq->cqe.user_data = poll_update->new_user_data; - ret2 = io_poll_add(preq, issue_flags); + ret2 = io_poll_add(preq, issue_flags & ~IO_URING_F_UNLOCKED); /* successfully updated, don't complete poll request */ if (!ret2 || ret2 == -EIOCBQUEUED) goto out; @@ -1043,9 +1042,9 @@ found: req_set_fail(preq); io_req_set_res(preq, -ECANCELED, 0); - locked = !(issue_flags & IO_URING_F_UNLOCKED); io_req_task_complete(preq, &locked); out: + io_ring_submit_unlock(ctx, issue_flags); if (ret < 0) { req_set_fail(req); return ret;