This is a note to let you know that I've just added the patch titled io_uring: fix poll requests leaking second poll entries to the 5.13-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: io_uring-fix-poll-requests-leaking-second-poll-entries.patch and it can be found in the queue-5.13 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From a890d01e4ee016978776e45340e521b3bbbdf41f Mon Sep 17 00:00:00 2001 From: Hao Xu <haoxu@xxxxxxxxxxxxxxxxx> Date: Wed, 28 Jul 2021 11:03:22 +0800 Subject: io_uring: fix poll requests leaking second poll entries From: Hao Xu <haoxu@xxxxxxxxxxxxxxxxx> commit a890d01e4ee016978776e45340e521b3bbbdf41f upstream. For pure poll requests, it doesn't remove the second poll wait entry when it's done, neither after vfs_poll() or in the poll completion handler. We should remove the second poll wait entry. And we use io_poll_remove_double() rather than io_poll_remove_waitqs() since the latter has some redundant logic. Fixes: 88e41cf928a6 ("io_uring: add multishot mode for IORING_OP_POLL_ADD") Cc: stable@xxxxxxxxxxxxxxx # 5.13+ Signed-off-by: Hao Xu <haoxu@xxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20210728030322.12307-1-haoxu@xxxxxxxxxxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- fs/io_uring.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -4924,7 +4924,6 @@ static bool io_poll_complete(struct io_k if (req->poll.events & EPOLLONESHOT) flags = 0; if (!io_cqring_fill_event(ctx, req->user_data, error, flags)) { - io_poll_remove_waitqs(req); req->poll.done = true; flags = 0; } @@ -4948,6 +4947,7 @@ static void io_poll_task_func(struct cal done = io_poll_complete(req, req->result); if (done) { + io_poll_remove_double(req); hash_del(&req->hash_node); } else { req->result = 0; @@ -5136,7 +5136,7 @@ static __poll_t __io_arm_poll_handler(st ipt->error = -EINVAL; spin_lock_irq(&ctx->completion_lock); - if (ipt->error) + if (ipt->error || (mask && (poll->events & EPOLLONESHOT))) io_poll_remove_double(req); if (likely(poll->head)) { spin_lock(&poll->head->lock); @@ -5207,7 +5207,6 @@ static bool io_arm_poll_handler(struct i ret = __io_arm_poll_handler(req, &apoll->poll, &ipt, mask, io_async_wake); if (ret || ipt.error) { - io_poll_remove_double(req); spin_unlock_irq(&ctx->completion_lock); return false; } Patches currently in stable-queue which might be from haoxu@xxxxxxxxxxxxxxxxx are queue-5.13/io_uring-fix-poll-requests-leaking-second-poll-entries.patch