public inbox for [email protected]
 help / color / mirror / Atom feed
From: Jens Axboe <[email protected]>
To: Oleg Nesterov <[email protected]>
Cc: [email protected], [email protected],
	[email protected], [email protected]
Subject: Re: [PATCH 2/6] kernel: add task_sigpending() helper
Date: Thu, 8 Oct 2020 07:38:05 -0600	[thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>

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


  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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    [email protected] \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox