The patch below does not apply to the 5.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

Possible dependencies:

7cfe7a09489c ("io_uring: clear TIF_NOTIFY_SIGNAL if set and task_work not available") 46a525e199e4 ("io_uring: don't gate task_work run on TIF_NOTIFY_SIGNAL") c0e0d6ba25f1 ("io_uring: add IORING_SETUP_DEFER_TASKRUN") b4c98d59a787 ("io_uring: introduce io_has_work") 78a861b94959 ("io_uring: add sync cancelation API through io_uring_register()") c34398a8c018 ("io_uring: remove __io_req_task_work_add") ed5ccb3beeba ("io_uring: remove priority tw list optimisation") 625d38b3fd34 ("io_uring: improve io_run_task_work()") 4a0fef62788b ("io_uring: optimize io_uring_task layout") 253993210bd8 ("io_uring: introduce locking helpers for CQE posting") 305bef988708 ("io_uring: hide eventfd assumptions in eventfd paths") affa87db9010 ("io_uring: fix multi ctx cancellation") d9dee4302a7c ("io_uring: remove ->flush_cqes optimisation") a830ffd28780 ("io_uring: move io_eventfd_signal()") 9046c6415be6 ("io_uring: reshuffle io_uring/io_uring.h") d142c3ec8d16 ("io_uring: remove extra io_commit_cqring()") 68494a65d0e2 ("io_uring: introduce io_req_cqe_overflow()") faf88dde060f ("io_uring: don't inline __io_get_cqe()") d245bca6375b ("io_uring: don't expose io_fill_cqe_aux()") 9ca9fb24d5fe ("io_uring: mutex locked poll hashing")

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 7cfe7a09489c1cefee7181e07b5f2bcbaebd9f41 Mon Sep 17 00:00:00 2001 From: Jens Axboe axboe@kernel.dk Date: Fri, 25 Nov 2022 09:36:29 -0700 Subject: [PATCH] io_uring: clear TIF_NOTIFY_SIGNAL if set and task_work not available

With how task_work is added and signaled, we can have TIF_NOTIFY_SIGNAL set and no task_work pending as it got run in a previous loop. Treat TIF_NOTIFY_SIGNAL like get_signal(), always clear it if set regardless of whether or not task_work is pending to run.

Cc: stable@vger.kernel.org Fixes: 46a525e199e4 ("io_uring: don't gate task_work run on TIF_NOTIFY_SIGNAL") Signed-off-by: Jens Axboe axboe@kernel.dk

diff --git a/io_uring/io_uring.h b/io_uring/io_uring.h index cef5ff924e63..50bc3af44953 100644 --- a/io_uring/io_uring.h +++ b/io_uring/io_uring.h @@ -238,9 +238,14 @@ static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx)

static inline int io_run_task_work(void) { + /* + * Always check-and-clear the task_work notification signal. With how + * signaling works for task_work, we can find it set with nothing to + * run. We need to clear it for that case, like get_signal() does. + */ + if (test_thread_flag(TIF_NOTIFY_SIGNAL)) + clear_notify_signal(); if (task_work_pending(current)) { - if (test_thread_flag(TIF_NOTIFY_SIGNAL)) - clear_notify_signal(); __set_current_state(TASK_RUNNING); task_work_run(); return 1;