This is a note to let you know that I've just added the patch titled io_uring: fix req->apoll_events to the 5.18-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-req-apoll_events.patch and it can be found in the queue-5.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 64dfab31418f72f02c810c2fe3d2c385a1612f1d Author: Pavel Begunkov <asml.silence@xxxxxxxxx> Date: Tue Jun 21 13:25:06 2022 +0100 io_uring: fix req->apoll_events [ Upstream commit aacf2f9f382c91df73f33317e28a4c34c8038986 ] apoll_events should be set once in the beginning of poll arming just as poll->events and not change after. However, currently io_uring resets it on each __io_poll_execute() for no clear reason. There is also a place in __io_arm_poll_handler() where we add EPOLLONESHOT to downgrade a multishot, but forget to do the same thing with ->apoll_events, which is buggy. Fixes: 81459350d581e ("io_uring: cache req->apoll->events in req->cflags") Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx> Reviewed-by: Hao Xu <howeyxu@xxxxxxxxxxx> Link: https://lore.kernel.org/r/0aef40399ba75b1a4d2c2e85e6e8fd93c02fc6e4.1655814213.git.asml.silence@xxxxxxxxx Signed-off-by: Jens Axboe <axboe@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/io_uring.c b/fs/io_uring.c index 1070d22a1c2b..38ecea726254 100644 --- a/fs/io_uring.c +++ b/fs/io_uring.c @@ -5984,7 +5984,8 @@ static void io_apoll_task_func(struct io_kiocb *req, bool *locked) io_req_complete_failed(req, ret); } -static void __io_poll_execute(struct io_kiocb *req, int mask, __poll_t events) +static void __io_poll_execute(struct io_kiocb *req, int mask, + __poll_t __maybe_unused events) { req->result = mask; /* @@ -5993,7 +5994,6 @@ static void __io_poll_execute(struct io_kiocb *req, int mask, __poll_t events) * CPU. We want to avoid pulling in req->apoll->events for that * case. */ - req->apoll_events = events; if (req->opcode == IORING_OP_POLL_ADD) req->io_task_work.func = io_poll_task_func; else @@ -6143,6 +6143,8 @@ static int __io_arm_poll_handler(struct io_kiocb *req, io_init_poll_iocb(poll, mask, io_poll_wake); poll->file = req->file; + req->apoll_events = poll->events; + ipt->pt._key = mask; ipt->req = req; ipt->error = 0; @@ -6173,8 +6175,10 @@ static int __io_arm_poll_handler(struct io_kiocb *req, if (mask) { /* can't multishot if failed, just queue the event we've got */ - if (unlikely(ipt->error || !ipt->nr_entries)) + if (unlikely(ipt->error || !ipt->nr_entries)) { poll->events |= EPOLLONESHOT; + req->apoll_events |= EPOLLONESHOT; + } __io_poll_execute(req, mask, poll->events); return 0; } @@ -6387,7 +6391,7 @@ static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe return -EINVAL; io_req_set_refcount(req); - req->apoll_events = poll->events = io_poll_parse_events(sqe, flags); + poll->events = io_poll_parse_events(sqe, flags); return 0; }