From: Pavel Begunkov <[email protected]>
To: Jens Axboe <[email protected]>, [email protected]
Subject: [PATCH 2/2] io_uring: fix lockup in io_fail_links()
Date: Fri, 24 Jul 2020 20:07:21 +0300 [thread overview]
Message-ID: <83e0a9c08acce807764b6f86a31660963ee2e367.1595610422.git.asml.silence@gmail.com> (raw)
In-Reply-To: <[email protected]>
io_fail_links() doesn't consider REQ_F_COMP_LOCKED leading to nested
spin_lock(completion_lock) and lockup.
[ 197.680409] rcu: INFO: rcu_preempt detected expedited stalls on
CPUs/tasks: { 6-... } 18239 jiffies s: 1421 root: 0x40/.
[ 197.680411] rcu: blocking rcu_node structures:
[ 197.680412] Task dump for CPU 6:
[ 197.680413] link-timeout R running task 0 1669
1 0x8000008a
[ 197.680414] Call Trace:
[ 197.680420] ? io_req_find_next+0xa0/0x200
[ 197.680422] ? io_put_req_find_next+0x2a/0x50
[ 197.680423] ? io_poll_task_func+0xcf/0x140
[ 197.680425] ? task_work_run+0x67/0xa0
[ 197.680426] ? do_exit+0x35d/0xb70
[ 197.680429] ? syscall_trace_enter+0x187/0x2c0
[ 197.680430] ? do_group_exit+0x43/0xa0
[ 197.680448] ? __x64_sys_exit_group+0x18/0x20
[ 197.680450] ? do_syscall_64+0x52/0xa0
[ 197.680452] ? entry_SYSCALL_64_after_hwframe+0x44/0xa9
Signed-off-by: Pavel Begunkov <[email protected]>
---
fs/io_uring.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 98e8079e67e7..493e5047e67c 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -4199,10 +4199,9 @@ static void io_poll_task_handler(struct io_kiocb *req, struct io_kiocb **nxt)
hash_del(&req->hash_node);
io_poll_complete(req, req->result, 0);
- req->flags |= REQ_F_COMP_LOCKED;
- io_put_req_find_next(req, nxt);
spin_unlock_irq(&ctx->completion_lock);
+ io_put_req_find_next(req, nxt);
io_cqring_ev_posted(ctx);
}
--
2.24.0
next prev parent reply other threads:[~2020-07-24 17:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-24 17:07 [PATCH 0/2] two 5.8 fixes Pavel Begunkov
2020-07-24 17:07 ` [PATCH 1/2] io_uring: fix ->work corruption with poll_add Pavel Begunkov
2020-07-24 17:15 ` Pavel Begunkov
2020-07-24 17:07 ` Pavel Begunkov [this message]
2020-07-24 19:23 ` [PATCH 0/2] two 5.8 fixes Jens Axboe
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