From: Pavel Begunkov <asml.silence@gmail.com>
To: Jens Axboe <axboe@kernel.dk>, io-uring@vger.kernel.org
Subject: [PATCH 4/4] io-wq: cancel unbounded works on io-wq destroy
Date: Thu, 8 Apr 2021 01:54:42 +0100 [thread overview]
Message-ID: <cd4b543154154cba055cf86f351441c2174d7f71.1617842918.git.asml.silence@gmail.com> (raw)
In-Reply-To: <cover.1617842918.git.asml.silence@gmail.com>
WARNING: CPU: 5 PID: 227 at fs/io_uring.c:8578 io_ring_exit_work+0xe6/0x470
RIP: 0010:io_ring_exit_work+0xe6/0x470
Call Trace:
process_one_work+0x206/0x400
worker_thread+0x4a/0x3d0
kthread+0x129/0x170
ret_from_fork+0x22/0x30
INFO: task lfs-openat:2359 blocked for more than 245 seconds.
task:lfs-openat state:D stack: 0 pid: 2359 ppid: 1 flags:0x00000004
Call Trace:
...
wait_for_completion+0x8b/0xf0
io_wq_destroy_manager+0x24/0x60
io_wq_put_and_exit+0x18/0x30
io_uring_clean_tctx+0x76/0xa0
__io_uring_files_cancel+0x1b9/0x2e0
do_exit+0xc0/0xb40
...
Even after io-wq destroy has been issued io-wq worker threads will
continue executing all left work items as usual, and may hang waiting
for I/O that won't ever complete (aka unbounded).
[<0>] pipe_read+0x306/0x450
[<0>] io_iter_do_read+0x1e/0x40
[<0>] io_read+0xd5/0x330
[<0>] io_issue_sqe+0xd21/0x18a0
[<0>] io_wq_submit_work+0x6c/0x140
[<0>] io_worker_handle_work+0x17d/0x400
[<0>] io_wqe_worker+0x2c0/0x330
[<0>] ret_from_fork+0x22/0x30
Cancel all unbounded I/O instead of executing them. This changes the
user visible behaviour, but that's inevitable as io-wq is not per task.
Suggested-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
---
fs/io-wq.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/fs/io-wq.c b/fs/io-wq.c
index 433c4d3c3c1c..4eba531bea5a 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -415,6 +415,7 @@ static void io_worker_handle_work(struct io_worker *worker)
{
struct io_wqe *wqe = worker->wqe;
struct io_wq *wq = wqe->wq;
+ bool do_kill = test_bit(IO_WQ_BIT_EXIT, &wq->state);
do {
struct io_wq_work *work;
@@ -444,6 +445,9 @@ static void io_worker_handle_work(struct io_worker *worker)
unsigned int hash = io_get_work_hash(work);
next_hashed = wq_next_work(work);
+
+ if (unlikely(do_kill) && (work->flags & IO_WQ_WORK_UNBOUND))
+ work->flags |= IO_WQ_WORK_CANCEL;
wq->do_work(work);
io_assign_current_work(worker, NULL);
--
2.24.0
next prev parent reply other threads:[~2021-04-08 0:59 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-08 0:54 [PATCH 5.12 0/4] 5.12 fixes Pavel Begunkov
2021-04-08 0:54 ` [PATCH 1/4] io_uring: clear F_REISSUE right after getting it Pavel Begunkov
2021-04-08 0:54 ` [PATCH 2/4] io_uring: fix rw req completion Pavel Begunkov
2021-04-08 0:54 ` [PATCH 3/4] io_uring: fix poll_rewait racing for ->canceled Pavel Begunkov
2021-04-08 2:28 ` Pavel Begunkov
2021-04-08 0:54 ` Pavel Begunkov [this message]
2021-04-08 4:11 ` [PATCH 5.12 0/4] 5.12 fixes Jens Axboe
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