* [PATCH] io_uring: don't submit sqes when ctx->refs is dying
@ 2021-02-19 17:58 Hao Xu
2021-02-19 18:04 ` Pavel Begunkov
0 siblings, 1 reply; 2+ messages in thread
From: Hao Xu @ 2021-02-19 17:58 UTC (permalink / raw)
To: Jens Axboe; +Cc: io-uring, Pavel Begunkov, Joseph Qi
When doing __io_uring_register() and waiting for references to exit,
there could be other threads calling io_uring_enter() and submitting
sqes which may cause the drain wait endless. So avoid this case by
checking if ctx->refs is dying.
Signed-off-by: Hao Xu <[email protected]>
---
fs/io_uring.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/io_uring.c b/fs/io_uring.c
index 931671082e61..9aab4d25c2df 100644
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -9356,6 +9356,8 @@ static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz
}
submitted = to_submit;
} else if (to_submit) {
+ if (unlikely(percpu_ref_is_dying(&ctx->refs)))
+ goto out;
ret = io_uring_add_task_file(ctx, f.file);
if (unlikely(ret))
goto out;
--
1.8.3.1
^ permalink raw reply related [flat|nested] 2+ messages in thread* Re: [PATCH] io_uring: don't submit sqes when ctx->refs is dying
2021-02-19 17:58 [PATCH] io_uring: don't submit sqes when ctx->refs is dying Hao Xu
@ 2021-02-19 18:04 ` Pavel Begunkov
0 siblings, 0 replies; 2+ messages in thread
From: Pavel Begunkov @ 2021-02-19 18:04 UTC (permalink / raw)
To: Hao Xu, Jens Axboe; +Cc: io-uring, Joseph Qi
On 19/02/2021 17:58, Hao Xu wrote:
> When doing __io_uring_register() and waiting for references to exit,
> there could be other threads calling io_uring_enter() and submitting
> sqes which may cause the drain wait endless. So avoid this case by
> checking if ctx->refs is dying.
IMHO, let's leave it as is because it noticeably changes behaviour.
That's nothing that can't be solved in userspace if needed differently.
>
> Signed-off-by: Hao Xu <[email protected]>
> ---
> fs/io_uring.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index 931671082e61..9aab4d25c2df 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -9356,6 +9356,8 @@ static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz
> }
> submitted = to_submit;
> } else if (to_submit) {
> + if (unlikely(percpu_ref_is_dying(&ctx->refs)))
> + goto out;
> ret = io_uring_add_task_file(ctx, f.file);
> if (unlikely(ret))
> goto out;
>
--
Pavel Begunkov
^ permalink raw reply [flat|nested] 2+ messages in thread
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