From: Jens Axboe <axboe@kernel.dk>
To: Oleg Nesterov <oleg@redhat.com>
Cc: linux-kernel@vger.kernel.org, io-uring@vger.kernel.org,
peterz@infradead.org, tglx@linutronix.de
Subject: Re: [PATCH 2/6] kernel: add task_sigpending() helper
Date: Thu, 8 Oct 2020 07:38:05 -0600 [thread overview]
Message-ID: <99b7ebb1-0cf8-7605-bf2f-08e7abc9cf43@kernel.dk> (raw)
In-Reply-To: <20201008132444.GF9995@redhat.com>
On 10/8/20 7:24 AM, Oleg Nesterov wrote:
> On 10/05, Jens Axboe wrote:
>>
>> @@ -4447,7 +4447,7 @@ SYSCALL_DEFINE0(pause)
>> __set_current_state(TASK_INTERRUPTIBLE);
>> schedule();
>> }
>> - return -ERESTARTNOHAND;
>> + return task_sigpending(current) ? -ERESTARTNOHAND : -ERESTARTSYS;
>> }
>>
>> #endif
>> @@ -4462,7 +4462,7 @@ static int sigsuspend(sigset_t *set)
>> schedule();
>> }
>> set_restore_sigmask();
>> - return -ERESTARTNOHAND;
>> + return task_sigpending(current) ? -ERESTARTNOHAND : -ERESTARTSYS;
>> }
>
> Both changes are equally wrong. Why do you think sigsuspend() should ever
> return -ERESTARTSYS ?
>
> If get_signal() deques a signal, handle_signal() will restart this syscall
> if ERESTARTSYS, this is wrong.
The intent was that if we get woken up and signal_pending() is true, then
we want to restart it if we're just doing TIF_SIGNAL_NOTIFY. But I guess
it can't be 100% reliable, even if TIF_SIGPENDING isn't set at this point,
but it is by the time a signal is attempted dequeued.
I'll drop these too, thanks Oleg.
--
Jens Axboe
next prev parent reply other threads:[~2020-10-08 13:38 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-05 15:04 [PATCHSET RFC v3 0/6] Add support for TIF_NOTIFY_SIGNAL Jens Axboe
2020-10-05 15:04 ` [PATCH 1/6] tracehook: clear TIF_NOTIFY_RESUME in tracehook_notify_resume() Jens Axboe
2020-10-08 12:37 ` Oleg Nesterov
2020-10-08 13:36 ` Jens Axboe
2020-10-05 15:04 ` [PATCH 2/6] kernel: add task_sigpending() helper Jens Axboe
2020-10-08 12:58 ` Oleg Nesterov
2020-10-08 13:36 ` Jens Axboe
2020-10-08 13:24 ` Oleg Nesterov
2020-10-08 13:38 ` Jens Axboe [this message]
2020-10-05 15:04 ` [PATCH 3/6] kernel: split syscall restart from signal handling Jens Axboe
2020-10-08 14:21 ` Oleg Nesterov
2020-10-08 14:31 ` Jens Axboe
2020-10-08 14:41 ` Jens Axboe
2020-10-08 14:45 ` Oleg Nesterov
2020-10-08 14:47 ` Jens Axboe
2020-10-05 15:04 ` [PATCH 4/6] kernel: add support for TIF_NOTIFY_SIGNAL Jens Axboe
2020-10-08 13:53 ` Oleg Nesterov
2020-10-08 14:07 ` Jens Axboe
2020-10-08 14:27 ` Oleg Nesterov
2020-10-05 15:04 ` [PATCH 5/6] x86: define _TIF_NOTIFY_SIGNAL Jens Axboe
2020-10-05 15:04 ` [PATCH 6/6] task_work: use TIF_NOTIFY_SIGNAL if available Jens Axboe
2020-10-08 14:56 ` [PATCHSET RFC v3 0/6] Add support for TIF_NOTIFY_SIGNAL Oleg Nesterov
2020-10-08 15:00 ` Jens Axboe
2020-10-09 8:01 ` Miroslav Benes
2020-10-09 15:21 ` Jens Axboe
2020-10-10 16:53 ` Jens Axboe
2020-10-12 17:27 ` Miroslav Benes
2020-10-13 19:39 ` Jens Axboe
2020-10-13 23:34 ` Thomas Gleixner
2020-10-13 23:37 ` Jens Axboe
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