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io_uring: complete request via task work in case of DEFER_TASKRUN 

commit 860e1c7f8b 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: e6aeb2721d ("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@kernel.dk/
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>
This commit is contained in:
Ming Lei 2023-04-14 15:53:13 +08:00 committed by Greg Kroah-Hartman
parent 0610761d3e
commit fda4233d24
1 changed files with 1 additions and 1 deletions
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2
io_uring/io_uring.c
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@ -962,7 +962,7 @@ static void __io_req_complete_post(struct io_kiocb *req)
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) ||