This is a note to let you know that I've just added the patch titled
io_uring: complete request via task work in case of DEFER_TASKRUN
to the 6.2-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
io_uring-complete-request-via-task-work-in-case-of-defer_taskrun.patch
and it can be found in the queue-6.2 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 860e1c7f8b0b43fbf91b4d689adfaa13adb89452 Mon Sep 17 00:00:00 2001
From: Ming Lei <ming.lei@xxxxxxxxxx>
Date: Fri, 14 Apr 2023 15:53:13 +0800
Subject: io_uring: complete request via task work in case of DEFER_TASKRUN
From: Ming Lei <ming.lei@xxxxxxxxxx>
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@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/linux-block/b3fc9991-4c53-9218-a8cc-5b4dd3952108@xxxxxxxxx/
Reported-by: Jens Axboe <axboe@xxxxxxxxx>
Cc: Kanchan Joshi <joshi.k@xxxxxxxxxxx>
Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx>
Signed-off-by: Jens Axboe <axboe@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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) ||
Patches currently in stable-queue which might be from ming.lei@xxxxxxxxxx are
queue-6.2/io_uring-complete-request-via-task-work-in-case-of-defer_taskrun.patch
