* [PATCH] io-wq: exclusively gate signal based exit on get_signal() return
@ 2021-09-27 16:58 Jens Axboe
2021-09-27 17:00 ` Eric W. Biederman
0 siblings, 1 reply; 2+ messages in thread
From: Jens Axboe @ 2021-09-27 16:58 UTC (permalink / raw)
To: io-uring; +Cc: Eric W. Biederman, Linus Torvalds
io-wq threads block all signals, except SIGKILL and SIGSTOP. We should not
need any extra checking of signal_pending or fatal_signal_pending, rely
exclusively on whether or not get_signal() tells us to exit.
The original debugging of this issue led to the false positive that we
were exiting on non-fatal signals, but that is not the case. The issue
was around races with nr_workers accounting.
Fixes: 87c169665578 ("io-wq: ensure we exit if thread group is exiting")
Fixes: 15e20db2e0ce ("io-wq: only exit on fatal signals")
Reported-by: Eric W. Biederman <[email protected]>
Reported-by: Linus Torvalds <[email protected]>
Signed-off-by: Jens Axboe <[email protected]>
---
diff --git a/fs/io-wq.c b/fs/io-wq.c
index c2360cdc403d..5bf8aa81715e 100644
--- a/fs/io-wq.c
+++ b/fs/io-wq.c
@@ -584,10 +584,7 @@ static int io_wqe_worker(void *data)
if (!get_signal(&ksig))
continue;
- if (fatal_signal_pending(current) ||
- signal_group_exit(current->signal))
- break;
- continue;
+ break;
}
last_timeout = !ret;
}
--
Jens Axboe
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] io-wq: exclusively gate signal based exit on get_signal() return
2021-09-27 16:58 [PATCH] io-wq: exclusively gate signal based exit on get_signal() return Jens Axboe
@ 2021-09-27 17:00 ` Eric W. Biederman
0 siblings, 0 replies; 2+ messages in thread
From: Eric W. Biederman @ 2021-09-27 17:00 UTC (permalink / raw)
To: Jens Axboe; +Cc: io-uring, Linus Torvalds
Jens Axboe <[email protected]> writes:
> io-wq threads block all signals, except SIGKILL and SIGSTOP. We should not
> need any extra checking of signal_pending or fatal_signal_pending, rely
> exclusively on whether or not get_signal() tells us to exit.
>
> The original debugging of this issue led to the false positive that we
> were exiting on non-fatal signals, but that is not the case. The issue
> was around races with nr_workers accounting.
Acked-by: "Eric W. Biederman" <[email protected]>
>
> Fixes: 87c169665578 ("io-wq: ensure we exit if thread group is exiting")
> Fixes: 15e20db2e0ce ("io-wq: only exit on fatal signals")
> Reported-by: Eric W. Biederman <[email protected]>
> Reported-by: Linus Torvalds <[email protected]>
> Signed-off-by: Jens Axboe <[email protected]>
>
> ---
>
> diff --git a/fs/io-wq.c b/fs/io-wq.c
> index c2360cdc403d..5bf8aa81715e 100644
> --- a/fs/io-wq.c
> +++ b/fs/io-wq.c
> @@ -584,10 +584,7 @@ static int io_wqe_worker(void *data)
>
> if (!get_signal(&ksig))
> continue;
> - if (fatal_signal_pending(current) ||
> - signal_group_exit(current->signal))
> - break;
> - continue;
> + break;
> }
> last_timeout = !ret;
> }
^ permalink raw reply [flat|nested] 2+ messages in thread
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2021-09-27 16:58 [PATCH] io-wq: exclusively gate signal based exit on get_signal() return Jens Axboe
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