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From: Oleg Nesterov <oleg@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Deepa Dinamani <deepa.kernel@gmail.com>,
	linux-kernel@vger.kernel.org, arnd@arndb.de, dbueso@suse.de,
	axboe@kernel.dk, dave@stgolabs.net, e@80x24.org,
	jbaron@akamai.com, linux-fsdevel@vger.kernel.org,
	linux-aio@kvack.org, omar.kilani@gmail.com, tglx@linutronix.de,
	Al Viro <viro@ZenIV.linux.org.uk>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	David Laight <David.Laight@ACULAB.COM>,
	linux-arch@vger.kernel.org
Subject: Re: [RFC PATCH 1/5] signal: Teach sigsuspend to use set_user_sigmask
Date: Mon, 10 Jun 2019 18:22:45 +0200	[thread overview]
Message-ID: <20190610162244.GB8127@redhat.com> (raw)
In-Reply-To: <87ef45axa4.fsf_-_@xmission.com>

On 06/07, Eric W. Biederman wrote:
>
> +static int set_sigmask(sigset_t *kmask)
> +{
> +	set_restore_sigmask();
> +	current->saved_sigmask = current->blocked;
> +	set_current_blocked(kmask);
> +
> +	return 0;
> +}

I was going to do the same change except my version returns void ;)

So ACK.


As for 2-5, sorry I can't read them today, will do tomorrow.

But at first glance... yes, we can remove TIF_RESTORE_SIGMASK.

As for "remove saved_sigmask" I have some concerns... At least this
means a user-visible change iiuc. Say, pselect unblocks a fatal signal.
Say, SIGINT without a handler. Suppose SIGINT comes after set_sigmask().

Before this change the process will be killed.

After this change it will be killed or not. It won't be killed if
do_select() finds an already ready fd without blocking, or it finds a
ready fd right after SIGINT interrupts poll_schedule_timeout().

And _to me_ the new behaviour makes more sense. But when it comes to
user-visible changes you can never know if it breaks something or not.

Oleg.

  parent reply	other threads:[~2019-06-10 16:22 UTC|newest]

Thread overview: 60+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20190522032144.10995-1-deepa.kernel@gmail.com>
     [not found] ` <20190529161157.GA27659@redhat.com>
     [not found]   ` <20190604134117.GA29963@redhat.com>
     [not found]     ` <20190606140814.GA13440@redhat.com>
2019-06-07 21:39       ` [RFC PATCH 0/5]: Removing saved_sigmask Eric W. Biederman
2019-06-07 21:39         ` Eric W. Biederman
2019-06-07 21:41         ` [RFC PATCH 1/5] signal: Teach sigsuspend to use set_user_sigmask Eric W. Biederman
2019-06-07 21:41           ` Eric W. Biederman
2019-06-07 22:07           ` Linus Torvalds
2019-06-07 22:07             ` Linus Torvalds
2019-06-10 16:22           ` Oleg Nesterov [this message]
2019-06-10 16:22             ` Oleg Nesterov
2019-06-10 21:20             ` Eric W. Biederman
2019-06-10 21:20               ` Eric W. Biederman
2019-06-11  9:52               ` David Laight
2019-06-11  9:52                 ` David Laight
2019-06-11 11:14                 ` David Laight
2019-06-11 11:14                   ` David Laight
2019-06-12 12:55                   ` Eric W. Biederman
2019-06-12 12:55                     ` Eric W. Biederman
2019-06-12 13:24                     ` David Laight
2019-06-12 13:24                       ` David Laight
2019-06-12 13:35                       ` Oleg Nesterov
2019-06-12 13:35                         ` Oleg Nesterov
2019-06-12 13:39                         ` David Laight
2019-06-12 13:39                           ` David Laight
2019-06-11 15:46                 ` David Laight
2019-06-11 15:46                   ` David Laight
2019-06-12 12:40                   ` Eric W. Biederman
2019-06-12 12:40                     ` Eric W. Biederman
2019-06-12 13:45                 ` Oleg Nesterov
2019-06-12 13:45                   ` Oleg Nesterov
2019-06-12 14:18                   ` David Laight
2019-06-12 14:18                     ` David Laight
2019-06-12 15:11                     ` Eric W. Biederman
2019-06-12 15:11                       ` Eric W. Biederman
2019-06-12 15:37                       ` Oleg Nesterov
2019-06-12 15:37                         ` Oleg Nesterov
2019-06-13  8:48                     ` David Laight
2019-06-13  8:48                       ` David Laight
2019-06-13  9:43                       ` Oleg Nesterov
2019-06-13  9:43                         ` Oleg Nesterov
2019-06-13 10:56                         ` David Laight
2019-06-13 10:56                           ` David Laight
2019-06-13 12:43                           ` Oleg Nesterov
2019-06-13 12:43                             ` Oleg Nesterov
2019-06-11 18:55               ` Oleg Nesterov
2019-06-11 18:55                 ` Oleg Nesterov
2019-06-11 19:02                 ` Eric W. Biederman
2019-06-11 19:02                   ` Eric W. Biederman
2019-06-12  8:39                 ` David Laight
2019-06-12  8:39                   ` David Laight
2019-06-12 13:09                   ` Eric W. Biederman
2019-06-12 13:09                     ` Eric W. Biederman
2019-06-07 21:41         ` [RFC PATCH 2/5] signal/kvm: Stop using sigprocmask in kvm_sigset_(activate|deactivate) Eric W. Biederman
2019-06-07 21:41           ` Eric W. Biederman
2019-06-07 21:42         ` [RFC PATCH 3/5] signal: Always keep real_blocked in sync with blocked Eric W. Biederman
2019-06-07 21:42           ` Eric W. Biederman
2019-06-07 21:43         ` [RFC PATCH 4/5] signal: Remove saved_sigmask Eric W. Biederman
2019-06-07 21:43           ` Eric W. Biederman
2019-06-07 21:44         ` [RFC PATCH 5/5] signal: Remove the unnecessary restore_sigmask flag Eric W. Biederman
2019-06-07 21:44           ` Eric W. Biederman
2019-06-11 18:58         ` [RFC PATCH 0/5]: Removing saved_sigmask Oleg Nesterov
2019-06-11 18:58           ` Oleg Nesterov

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