6.12-stable review patch. If anyone has any objections, please let me know.
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From: Jens Axboe axboe@kernel.dk
Commit 3539b1467e94336d5854ebf976d9627bfb65d6c3 upstream.
When running task_work for an exiting task, rather than perform the issue retry attempt, the task_work is canceled. However, this isn't done for a ring that has been closed. This can lead to requests being successfully completed post the ring being closed, which is somewhat confusing and surprising to an application.
Rather than just check the task exit state, also include the ring ref state in deciding whether or not to terminate a given request when run from task_work.
Cc: stable@vger.kernel.org # 6.1+ Link: https://github.com/axboe/liburing/discussions/1459 Reported-by: Benedek Thaler thaler@thaler.hu Signed-off-by: Jens Axboe axboe@kernel.dk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- io_uring/io_uring.c | 6 ++++-- io_uring/io_uring.h | 4 ++-- io_uring/poll.c | 2 +- io_uring/timeout.c | 2 +- io_uring/uring_cmd.c | 2 +- 5 files changed, 9 insertions(+), 7 deletions(-)
--- a/io_uring/io_uring.c +++ b/io_uring/io_uring.c @@ -1358,8 +1358,10 @@ static void io_req_task_cancel(struct io
void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts) { - io_tw_lock(req->ctx, ts); - if (unlikely(io_should_terminate_tw())) + struct io_ring_ctx *ctx = req->ctx; + + io_tw_lock(ctx, ts); + if (unlikely(io_should_terminate_tw(ctx))) io_req_defer_failed(req, -EFAULT); else if (req->flags & REQ_F_FORCE_ASYNC) io_queue_iowq(req); --- a/io_uring/io_uring.h +++ b/io_uring/io_uring.h @@ -429,9 +429,9 @@ static inline bool io_allowed_run_tw(str * 2) PF_KTHREAD is set, in which case the invoker of the task_work is * our fallback task_work. */ -static inline bool io_should_terminate_tw(void) +static inline bool io_should_terminate_tw(struct io_ring_ctx *ctx) { - return current->flags & (PF_KTHREAD | PF_EXITING); + return (current->flags & (PF_KTHREAD | PF_EXITING)) || percpu_ref_is_dying(&ctx->refs); }
static inline void io_req_queue_tw_complete(struct io_kiocb *req, s32 res) --- a/io_uring/poll.c +++ b/io_uring/poll.c @@ -265,7 +265,7 @@ static int io_poll_check_events(struct i { int v;
- if (unlikely(io_should_terminate_tw())) + if (unlikely(io_should_terminate_tw(req->ctx))) return -ECANCELED;
do { --- a/io_uring/timeout.c +++ b/io_uring/timeout.c @@ -303,7 +303,7 @@ static void io_req_task_link_timeout(str int ret = -ENOENT;
if (prev) { - if (!io_should_terminate_tw()) { + if (!io_should_terminate_tw(req->ctx)) { struct io_cancel_data cd = { .ctx = req->ctx, .data = prev->cqe.user_data, --- a/io_uring/uring_cmd.c +++ b/io_uring/uring_cmd.c @@ -118,7 +118,7 @@ static void io_uring_cmd_work(struct io_ struct io_uring_cmd *ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd); unsigned int flags = IO_URING_F_COMPLETE_DEFER;
- if (io_should_terminate_tw()) + if (io_should_terminate_tw(req->ctx)) flags |= IO_URING_F_TASK_DEAD;
/* task_work executor checks the deffered list completion */