From: Jens Axboe <[email protected]>
To: [email protected]
Cc: Jens Axboe <[email protected]>
Subject: [PATCH 24/27] io_uring: always wait for sqd exited when stopping SQPOLL thread
Date: Wed, 10 Mar 2021 15:43:55 -0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
We have a tiny race where io_put_sq_data() calls io_sq_thead_stop()
and finds the thread gone, but the thread has indeed not fully
exited or called complete() yet. Close it up by always having
io_sq_thread_stop() wait on completion of the exit event.
Signed-off-by: Jens Axboe <[email protected]>
---
fs/io_uring.c | 16 ++++++++--------
1 file changed, 8 insertions(+), 8 deletions(-)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 6325f32ef6a3..62f998bf2ce8 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -7079,12 +7079,9 @@ static void io_sq_thread_stop(struct io_sq_data *sqd)
if (test_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state))
return;
down_write(&sqd->rw_lock);
- if (!sqd->thread) {
- up_write(&sqd->rw_lock);
- return;
- }
set_bit(IO_SQ_THREAD_SHOULD_STOP, &sqd->state);
- wake_up_process(sqd->thread);
+ if (sqd->thread)
+ wake_up_process(sqd->thread);
up_write(&sqd->rw_lock);
wait_for_completion(&sqd->exited);
}
@@ -7849,9 +7846,9 @@ static int io_sq_offload_create(struct io_ring_ctx *ctx,
ret = -EINVAL;
if (cpu >= nr_cpu_ids)
- goto err;
+ goto err_sqpoll;
if (!cpu_online(cpu))
- goto err;
+ goto err_sqpoll;
sqd->sq_cpu = cpu;
} else {
@@ -7862,7 +7859,7 @@ static int io_sq_offload_create(struct io_ring_ctx *ctx,
tsk = create_io_thread(io_sq_thread, sqd, NUMA_NO_NODE);
if (IS_ERR(tsk)) {
ret = PTR_ERR(tsk);
- goto err;
+ goto err_sqpoll;
}
sqd->thread = tsk;
@@ -7881,6 +7878,9 @@ static int io_sq_offload_create(struct io_ring_ctx *ctx,
err:
io_sq_thread_finish(ctx);
return ret;
+err_sqpoll:
+ complete(&ctx->sq_data->exited);
+ goto err;
}
static inline void __io_unaccount_mem(struct user_struct *user,
--
2.30.2
next prev parent reply other threads:[~2021-03-10 22:45 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-10 22:43 [PATCHSET for 5.12] Patches queued up for 5.12 Jens Axboe
2021-03-10 22:43 ` [PATCH 01/27] io-wq: fix race in freeing 'wq' and worker access Jens Axboe
2021-03-10 22:43 ` [PATCH 02/27] io-wq: always track creds for async issue Jens Axboe
2021-03-10 22:43 ` [PATCH 03/27] io_uring: make del_task_file more forgiving Jens Axboe
2021-03-10 22:43 ` [PATCH 04/27] io_uring: introduce ctx to tctx back map Jens Axboe
2021-03-10 22:43 ` [PATCH 05/27] io_uring: do ctx initiated file note removal Jens Axboe
2021-03-10 22:43 ` [PATCH 06/27] io_uring: don't take task ring-file notes Jens Axboe
2021-03-10 22:43 ` [PATCH 07/27] io_uring: index io_uring->xa by ctx not file Jens Axboe
2021-03-10 22:43 ` [PATCH 08/27] io_uring: warn when ring exit takes too long Jens Axboe
2021-03-10 22:43 ` [PATCH 09/27] io_uring: cancel reqs of all iowq's on ring exit Jens Axboe
2021-03-10 22:43 ` [PATCH 10/27] io-wq: warn on creating manager while exiting Jens Axboe
2021-03-10 22:43 ` [PATCH 11/27] io_uring: run __io_sq_thread() with the initial creds from io_uring_setup() Jens Axboe
2021-03-10 22:43 ` [PATCH 12/27] io_uring: kill io_sq_thread_fork() and return -EOWNERDEAD if the sq_thread is gone Jens Axboe
2021-03-10 22:43 ` [PATCH 13/27] io_uring: SQPOLL parking fixes Jens Axboe
2021-03-10 22:43 ` [PATCH 14/27] io_uring: fix unrelated ctx reqs cancellation Jens Axboe
2021-03-10 22:43 ` [PATCH 15/27] io_uring: clean R_DISABLED startup mess Jens Axboe
2021-03-10 22:43 ` [PATCH 16/27] io_uring: Convert personality_idr to XArray Jens Axboe
2021-03-10 22:43 ` [PATCH 17/27] io-wq: remove unused 'user' member of io_wq Jens Axboe
2021-03-10 22:43 ` [PATCH 18/27] io_uring: fix io_sq_offload_create error handling Jens Axboe
2021-03-10 22:43 ` [PATCH 19/27] io_uring: add io_disarm_next() helper Jens Axboe
2021-03-10 22:43 ` [PATCH 20/27] io_uring: fix complete_post races for linked req Jens Axboe
2021-03-10 22:43 ` [PATCH 21/27] io-wq: fix ref leak for req in case of exit cancelations Jens Axboe
2021-03-10 22:43 ` [PATCH 22/27] io_uring: move all io_kiocb init early in io_init_req() Jens Axboe
2021-03-10 22:43 ` [PATCH 23/27] io_uring: remove unneeded variable 'ret' Jens Axboe
2021-03-10 22:43 ` Jens Axboe [this message]
2021-03-10 22:43 ` [PATCH 25/27] kernel: make IO threads unfreezable by default Jens Axboe
2021-03-10 22:43 ` [PATCH 26/27] io_uring: fix invalid ctx->sq_thread_idle Jens Axboe
2021-03-10 22:43 ` [PATCH 27/27] io_uring: remove indirect ctx into sqo injection Jens Axboe
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