io_uring: handle TIF_NOTIFY_RESUME when checking for task_work

commit b5d3ae202fbfe055aa2a8ae8524531ee1dcab717 upstream.

If TIF_NOTIFY_RESUME is set, then we need to call resume_user_mode_work()
for PF_IO_WORKER threads. They never return to usermode, hence never get
a chance to process any items that are marked by this flag. Most notably
this includes the final put of files, but also any throttling markers set
by block cgroups.

Cc: stable@vger.kernel.org # 5.10+
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/io_uring/io_uring.c b/io_uring/io_uring.c
index 51d6fbe17f7f34d9efa791becfb77a7bb9048fa9..9911b60f9645d6208023df0672841addfa8d6fe5 100644 (file)
--- a/io_uring/io_uring.c
+++ b/io_uring/io_uring.c
@@ -2463,6 +2463,13 @@ static inline unsigned int io_put_rw_kbuf(struct io_kiocb *req)
 
 static inline bool io_run_task_work(void)
 {
+       /*
+        * PF_IO_WORKER never returns to userspace, so check here if we have
+        * notify work that needs processing.
+        */
+       if (current->flags & PF_IO_WORKER &&
+           test_thread_flag(TIF_NOTIFY_RESUME))
+               tracehook_notify_resume(NULL);
        if (test_thread_flag(TIF_NOTIFY_SIGNAL) || current->task_works) {
                __set_current_state(TASK_RUNNING);
                tracehook_notify_signal();