From: Jens Axboe axboe@kernel.dk
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 --- io_uring/io_uring.h | 8 ++++++++ 1 file changed, 8 insertions(+)
--- a/io_uring/io_uring.h +++ b/io_uring/io_uring.h @@ -3,6 +3,7 @@
#include <linux/errno.h> #include <linux/lockdep.h> +#include <linux/resume_user_mode.h> #include <linux/io_uring_types.h> #include <uapi/linux/eventpoll.h> #include "io-wq.h" @@ -270,6 +271,13 @@ static inline int io_run_task_work(void) */ if (test_thread_flag(TIF_NOTIFY_SIGNAL)) clear_notify_signal(); + /* + * 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)) + resume_user_mode_work(NULL); if (task_work_pending(current)) { __set_current_state(TASK_RUNNING); task_work_run();