From: Ming Lei ming.lei@redhat.com
commit 860e1c7f8b0b43fbf91b4d689adfaa13adb89452 upstream.
So far io_req_complete_post() only covers DEFER_TASKRUN by completing request via task work when the request is completed from IOWQ.
However, uring command could be completed from any context, and if io uring is setup with DEFER_TASKRUN, the command is required to be completed from current context, otherwise wait on IORING_ENTER_GETEVENTS can't be wakeup, and may hang forever.
The issue can be observed on removing ublk device, but turns out it is one generic issue for uring command & DEFER_TASKRUN, so solve it in io_uring core code.
Fixes: e6aeb2721d3b ("io_uring: complete all requests in task context") Cc: stable@vger.kernel.org Link: https://lore.kernel.org/linux-block/b3fc9991-4c53-9218-a8cc-5b4dd3952108@ker... Reported-by: Jens Axboe axboe@kernel.dk Cc: Kanchan Joshi joshi.k@samsung.com Signed-off-by: Ming Lei ming.lei@redhat.com Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- io_uring/io_uring.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -962,7 +962,7 @@ static void __io_req_complete_post(struc
void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags) { - if (req->ctx->task_complete && (issue_flags & IO_URING_F_IOWQ)) { + if (req->ctx->task_complete && req->ctx->submitter_task != current) { req->io_task_work.func = io_req_task_complete; io_req_task_work_add(req); } else if (!(issue_flags & IO_URING_F_UNLOCKED) ||