From: Jens Axboe <axboe@xxxxxxxxx>
commit 7cfe7a09489c1cefee7181e07b5f2bcbaebd9f41 upstream.
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@xxxxxxxxxxxxxxx
Fixes: 46a525e199e4 ("io_uring: don't gate task_work run on TIF_NOTIFY_SIGNAL")
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
io_uring/io_uring.h | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
--- a/io_uring/io_uring.h
+++ b/io_uring/io_uring.h
@@ -229,9 +229,14 @@ static inline unsigned int io_sqring_ent
static inline bool 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;
