From: David Laight <David.Laight@ACULAB.COM>
To: "'Eric W. Biederman'" <ebiederm@xmission.com>,
Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Deepa Dinamani <deepa.kernel@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"arnd@arndb.de" <arnd@arndb.de>,
"dbueso@suse.de" <dbueso@suse.de>,
"axboe@kernel.dk" <axboe@kernel.dk>,
"dave@stgolabs.net" <dave@stgolabs.net>,
"e@80x24.org" <e@80x24.org>,
"jbaron@akamai.com" <jbaron@akamai.com>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-aio@kvack.org" <linux-aio@kvack.org>,
"omar.kilani@gmail.com" <omar.kilani@gmail.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
"Al Viro" <viro@ZenIV.linux.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>,
"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
Michael Kerrisk <mtk.manpages@gmail.com>
Subject: RE: [PATCH] signal: remove the wrong signal_pending() check in restore_user_sigmask()
Date: Tue, 4 Jun 2019 15:57:41 +0000 [thread overview]
Message-ID: <3b68788ea9114d08bdfdab575c8c29bb@AcuMS.aculab.com> (raw)
In-Reply-To: <87tvd5nz8i.fsf@xmission.com>
From: Eric W. Biederman
> Sent: 04 June 2019 16:32
...
> Michael is there any chance we can get this guarantee of the linux
> implementation of pselect and friends clearly documented. The guarantee
> that if the system call completes successfully we are guaranteed that
> no signal that is unblocked by using sigmask will be delivered?
The behaviour certainly needs documenting - the ToG docs are unclear.
I think you need stronger statement that the one above.
Maybe "signals will only be delivered (ie the handler called) if
the system call has to wait and the wait is interrupted by a signal.
(Even then pselect might find ready fd and return success.)
There is also the 'issue' of ERESTARTNOHAND.
Some of the system calls will return EINTR if the wait is interrupted
by a signal that doesn't have a handler, others get restarted.
I'm not at all sure about why there is a difference.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
WARNING: multiple messages have this Message-ID (diff)
From: David Laight <David.Laight@ACULAB.COM>
To: "'Eric W. Biederman'" <ebiederm@xmission.com>,
Oleg Nesterov <oleg@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Deepa Dinamani <deepa.kernel@gmail.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"arnd@arndb.de" <arnd@arndb.de>,
"dbueso@suse.de" <dbueso@suse.de>,
"axboe@kernel.dk" <axboe@kernel.dk>,
"dave@stgolabs.net" <dave@stgolabs.net>,
"e@80x24.org" <e@80x24.org>,
"jbaron@akamai.com" <jbaron@akamai.com>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-aio@kvack.org" <linux-aio@kvack.org>,
"omar.kilani@gmail.com" <omar.kilani@gmail.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"stable@vger.kernel.org" <stable@vger.kernel.org>,
Al Viro <viro@ZenIV.linux.org.uk>,
Linus Torvalds <torvalds@linux-foundation.org>,
"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
Michael Kerrisk <mtk.manpages@gmail.com>
Subject: RE: [PATCH] signal: remove the wrong signal_pending() check in restore_user_sigmask()
Date: Tue, 4 Jun 2019 15:57:41 +0000 [thread overview]
Message-ID: <3b68788ea9114d08bdfdab575c8c29bb@AcuMS.aculab.com> (raw)
In-Reply-To: <87tvd5nz8i.fsf@xmission.com>
From: Eric W. Biederman
> Sent: 04 June 2019 16:32
...
> Michael is there any chance we can get this guarantee of the linux
> implementation of pselect and friends clearly documented. The guarantee
> that if the system call completes successfully we are guaranteed that
> no signal that is unblocked by using sigmask will be delivered?
The behaviour certainly needs documenting - the ToG docs are unclear.
I think you need stronger statement that the one above.
Maybe "signals will only be delivered (ie the handler called) if
the system call has to wait and the wait is interrupted by a signal.
(Even then pselect might find ready fd and return success.)
There is also the 'issue' of ERESTARTNOHAND.
Some of the system calls will return EINTR if the wait is interrupted
by a signal that doesn't have a handler, others get restarted.
I'm not at all sure about why there is a difference.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
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next prev parent reply other threads:[~2019-06-04 15:57 UTC|newest]
Thread overview: 155+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-22 3:21 [PATCH v2] signal: Adjust error codes according to restore_user_sigmask() Deepa Dinamani
2019-05-22 15:05 ` Oleg Nesterov
2019-05-22 15:55 ` Deepa Dinamani
2019-05-22 16:14 ` Oleg Nesterov
2019-05-22 16:33 ` Deepa Dinamani
2019-05-23 9:03 ` David Laight
2019-05-23 14:59 ` Oleg Nesterov
2019-05-23 16:18 ` David Laight
2019-05-23 16:36 ` Oleg Nesterov
2019-05-23 16:56 ` David Laight
2019-05-23 18:06 ` Deepa Dinamani
2019-05-23 20:41 ` Deepa Dinamani
2019-05-23 21:06 ` Deepa Dinamani
2019-05-24 9:58 ` David Laight
2019-05-24 14:10 ` Oleg Nesterov
2019-05-24 15:16 ` Deepa Dinamani
2019-05-24 16:33 ` Oleg Nesterov
2019-05-24 17:01 ` Deepa Dinamani
2019-05-27 15:04 ` Oleg Nesterov
2019-05-28 20:47 ` Deepa Dinamani
2019-05-29 16:57 ` Oleg Nesterov
2019-05-29 18:42 ` Deepa Dinamani
2019-05-28 9:02 ` David Laight
2019-05-28 9:12 ` David Laight
2019-05-28 11:37 ` Deepa Dinamani
2019-05-28 12:04 ` David Laight
2019-05-24 14:19 ` Oleg Nesterov
2019-05-24 14:29 ` Deepa Dinamani
2019-05-24 14:51 ` Oleg Nesterov
2019-05-24 13:29 ` Oleg Nesterov
2019-05-24 14:59 ` David Laight
2019-05-24 15:09 ` David Laight
2019-05-24 15:46 ` Oleg Nesterov
2019-05-24 15:44 ` Oleg Nesterov
2019-05-24 16:40 ` David Laight
2019-05-23 14:33 ` Oleg Nesterov
2019-05-22 22:18 ` Chris Down
2019-05-22 22:52 ` Deepa Dinamani
2019-05-22 22:52 ` Deepa Dinamani
2019-05-29 16:11 ` pselect/etc semantics (Was: [PATCH v2] signal: Adjust error codes according to restore_user_sigmask()) Oleg Nesterov
2019-05-29 16:54 ` David Laight
2019-05-29 18:50 ` Eric Wong
2019-05-30 9:34 ` David Laight
2019-05-30 13:04 ` pselect/etc semantics Eric W. Biederman
2019-05-29 16:56 ` pselect/etc semantics (Was: [PATCH v2] signal: Adjust error codes according to restore_user_sigmask()) Deepa Dinamani
2019-05-29 18:26 ` Deepa Dinamani
2019-05-29 22:32 ` Arnd Bergmann
2019-05-30 1:54 ` pselect/etc semantics Eric W. Biederman
2019-05-30 18:28 ` Arnd Bergmann
2019-05-30 14:40 ` pselect/etc semantics (Was: [PATCH v2] signal: Adjust error codes according to restore_user_sigmask()) Oleg Nesterov
2019-05-30 18:37 ` Arnd Bergmann
2019-05-30 13:01 ` pselect/etc semantics Eric W. Biederman
2019-05-30 15:18 ` David Laight
2019-05-30 16:13 ` Oleg Nesterov
2019-05-30 15:38 ` Eric W. Biederman
2019-05-30 15:48 ` Deepa Dinamani
2019-05-30 16:59 ` Deepa Dinamani
2019-05-30 16:08 ` Oleg Nesterov
2019-05-30 17:20 ` Eric W. Biederman
2019-05-30 16:22 ` David Laight
2019-05-30 15:57 ` Oleg Nesterov
2019-05-30 21:03 ` Eric Wong
2019-06-04 13:41 ` [PATCH] signal: remove the wrong signal_pending() check in restore_user_sigmask() Oleg Nesterov
2019-06-04 15:31 ` Eric W. Biederman
2019-06-04 15:31 ` Eric W. Biederman
2019-06-04 15:57 ` David Laight [this message]
2019-06-04 15:57 ` David Laight
2019-06-04 16:37 ` Arnd Bergmann
2019-06-04 18:14 ` Deepa Dinamani
2019-06-04 18:35 ` Eric Wong
2019-06-04 21:26 ` Linus Torvalds
2019-06-04 22:24 ` Eric Wong
2019-06-04 23:51 ` Eric W. Biederman
2019-06-05 9:04 ` Oleg Nesterov
2019-06-05 8:56 ` Oleg Nesterov
2019-06-05 9:02 ` David Laight
2019-06-05 9:25 ` Oleg Nesterov
2019-06-05 9:58 ` David Laight
2019-06-05 15:58 ` [PATCH -mm 0/1] signal: simplify set_user_sigmask/restore_user_sigmask Oleg Nesterov
2019-06-05 15:58 ` [PATCH -mm 1/1] " Oleg Nesterov
2019-06-06 0:14 ` kbuild test robot
2019-06-06 1:06 ` kbuild test robot
2019-06-06 7:25 ` Oleg Nesterov
2019-06-06 7:30 ` Sedat Dilek
2019-06-05 17:24 ` [PATCH -mm 0/1] " Linus Torvalds
2019-06-06 9:05 ` David Laight
2019-06-06 11:05 ` Oleg Nesterov
2019-06-06 11:29 ` David Laight
2019-06-06 12:41 ` Oleg Nesterov
2019-06-06 13:23 ` David Laight
2019-06-06 10:22 ` Oleg Nesterov
2019-06-06 11:32 ` [PATCH -mm V2 1/1] " Oleg Nesterov
2019-06-06 14:08 ` [PATCH 0/2] select: simplify the usage of restore_saved_sigmask_unless() Oleg Nesterov
2019-06-06 14:08 ` [PATCH 1/2] select: change do_poll() to return -ERESTARTNOHAND rather than -EINTR Oleg Nesterov
2019-06-07 18:05 ` Linus Torvalds
2019-06-06 14:09 ` [PATCH 2/2] select: shift restore_saved_sigmask_unless() into poll_select_copy_remaining() Oleg Nesterov
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 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
2019-06-10 21:20 ` Eric W. Biederman
2019-06-11 9:52 ` 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 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 12:40 ` Eric W. Biederman
2019-06-12 13:45 ` Oleg Nesterov
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 19:02 ` Eric W. Biederman
2019-06-11 19:02 ` Eric W. Biederman
2019-06-12 8:39 ` David Laight
2019-06-12 13:09 ` Eric W. Biederman
2019-06-12 13:09 ` Eric W. Biederman
2019-06-12 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 21:41 ` 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 21:42 ` 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 21:43 ` 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
2019-06-07 21:44 ` Eric W. Biederman
2019-06-11 18:58 ` [RFC PATCH 0/5]: Removing saved_sigmask Oleg Nesterov
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