From: Matthew Garrett <mjg@redhat.com>
To: Tony Lindgren <tony@atomide.com>
Cc: "Alan Stern" <stern@rowland.harvard.edu>,
"Paul Walmsley" <paul@pwsan.com>,
"Arve Hjønnevåg" <arve@android.com>,
"Linux-pm mailing list" <linux-pm@lists.linux-foundation.org>,
"Kernel development list" <linux-kernel@vger.kernel.org>,
"Tejun Heo" <tj@kernel.org>, "Oleg Nesterov" <oleg@redhat.com>,
"Kevin Hilman" <khilman@deeprootsystems.com>,
magnus.damm@gmail.com, "Theodore Ts'o" <tytso@mit.edu>,
"mark gross" <mgross@linux.intel.com>,
"Arjan van de Ven" <arjan@infradead.org>,
"Geoff Smith" <geoffx.smith@intel.com>,
"Brian Swetland" <swetland@google.com>,
"Rafael J. Wysocki" <rjw@sisk.pl>,
"Benoît Cousson" <b-cousson@ti.com>,
linux-omap@vger.kernel.org, "Vitaly Wool" <vitalywool@gmail.com>,
"Mark Brown" <broonie@opensource.wolfsonmicro.com>,
"Liam Girdwood" <lrg@slimlogic.co.uk>
Subject: Re: [linux-pm] [PATCH 0/8] Suspend block api (version 6)
Date: Sat, 15 May 2010 20:54:01 +0100 [thread overview]
Message-ID: <20100515195401.GA29677@srcf.ucam.org> (raw)
In-Reply-To: <20100513213455.GK3428@atomide.com>
On Thu, May 13, 2010 at 02:34:55PM -0700, Tony Lindgren wrote:
> * Matthew Garrett <mjg@redhat.com> [100513 14:16]:
> > What race-free mechanism do you use to ensure that? It's very easy to
> > handwave these problems away. It's very difficult to actually write an
> > implementation that works.
>
> Can you describe where do you see the race now?
1) Trusted app decides to suspend
2) Network packet that would otherwise wake the system is received
3) Trusted app sends SIGSTOP to untrusted userspace
4) Network packet sits waiting for stopped userspace to process it
Unless the trusted userspace gets woken up on every event that would
potentially cause a wakeup, you're racy. And the alternative involves an
extra userspace wakeup for every network packet - which is expensive.
--
Matthew Garrett | mjg59@srcf.ucam.org
next prev parent reply other threads:[~2010-05-15 19:54 UTC|newest]
Thread overview: 323+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-04-30 22:36 [PATCH 0/8] Suspend block api (version 6) Arve Hjønnevåg
2010-04-30 22:36 ` [PATCH 1/8] PM: Add suspend block api Arve Hjønnevåg
2010-04-30 22:36 ` [PATCH 2/8] PM: suspend_block: Add driver to access suspend blockers from user-space Arve Hjønnevåg
2010-04-30 22:36 ` [PATCH 3/8] PM: suspend_block: Abort task freezing if a suspend_blocker is active Arve Hjønnevåg
2010-04-30 22:36 ` [PATCH 4/8] PM: suspend_block: Add debugfs file Arve Hjønnevåg
2010-04-30 22:36 ` [PATCH 5/8] PM: suspend_block: Add suspend_blocker stats Arve Hjønnevåg
2010-04-30 22:36 ` [PATCH 6/8] PM: Add suspend blocking work Arve Hjønnevåg
2010-04-30 22:37 ` [PATCH 7/8] Input: Block suspend while event queue is not empty Arve Hjønnevåg
2010-04-30 22:37 ` [PATCH 8/8] power_supply: Block suspend while power supply change notifications are pending Arve Hjønnevåg
2010-05-01 6:14 ` [PATCH 6/8] PM: Add suspend blocking work Tejun Heo
2010-05-02 7:05 ` Pavel Machek
2010-05-04 11:16 ` [PATCH 4/8] PM: suspend_block: Add debugfs file Andi Kleen
2010-05-04 21:06 ` Arve Hjønnevåg
2010-05-02 6:57 ` [PATCH 3/8] PM: suspend_block: Abort task freezing if a suspend_blocker is active Pavel Machek
2010-05-02 7:04 ` [PATCH 2/8] PM: suspend_block: Add driver to access suspend blockers from user-space Pavel Machek
2010-05-02 21:23 ` Rafael J. Wysocki
2010-05-02 21:56 ` Alan Stern
2010-05-03 15:03 ` Rafael J. Wysocki
2010-05-03 21:26 ` Arve Hjønnevåg
2010-05-03 21:49 ` Rafael J. Wysocki
2010-05-03 22:01 ` Arve Hjønnevåg
2010-05-04 20:02 ` Rafael J. Wysocki
2010-05-04 4:16 ` Pavel Machek
2010-05-02 6:56 ` [PATCH 1/8] PM: Add suspend block api Pavel Machek
2010-05-02 20:10 ` Rafael J. Wysocki
2010-05-02 20:52 ` Pavel Machek
2010-05-02 21:29 ` Rafael J. Wysocki
2010-05-03 19:01 ` Pavel Machek
2010-05-03 21:38 ` Rafael J. Wysocki
2010-05-03 22:11 ` Alan Stern
2010-05-03 22:24 ` Arve Hjønnevåg
2010-05-02 7:01 ` Pavel Machek
2010-05-04 5:12 ` [linux-pm] " mark gross
2010-05-04 13:59 ` Alan Stern
2010-05-04 16:03 ` mark gross
2010-05-04 17:16 ` Alan Stern
2010-05-05 1:50 ` mark gross
2010-05-05 13:31 ` Matthew Garrett
2010-05-05 20:09 ` mark gross
2010-05-05 20:21 ` Matthew Garrett
2010-05-05 15:44 ` Alan Stern
2010-05-05 20:28 ` mark gross
2010-05-05 21:12 ` Alan Stern
2010-05-05 21:37 ` Brian Swetland
2010-05-05 23:47 ` Tony Lindgren
2010-05-05 23:56 ` Brian Swetland
2010-05-06 0:05 ` Tony Lindgren
2010-05-06 4:16 ` Arve Hjønnevåg
2010-05-06 17:04 ` Tony Lindgren
2010-05-07 0:10 ` Arve Hjønnevåg
2010-05-07 15:54 ` Tony Lindgren
2010-05-28 6:43 ` Pavel Machek
2010-05-28 7:01 ` Arve Hjønnevåg
2010-05-06 13:40 ` Matthew Garrett
2010-05-06 17:01 ` Tony Lindgren
2010-05-06 17:09 ` Matthew Garrett
2010-05-06 17:14 ` Tony Lindgren
2010-05-06 17:22 ` Matthew Garrett
2010-05-06 17:38 ` Tony Lindgren
2010-05-06 17:43 ` Matthew Garrett
2010-05-06 18:33 ` Tony Lindgren
2010-05-06 18:44 ` Matthew Garrett
2010-05-07 2:05 ` Tony Lindgren
2010-05-07 17:12 ` Matthew Garrett
2010-05-07 17:35 ` Tony Lindgren
2010-05-07 17:50 ` Matthew Garrett
2010-05-07 18:01 ` Tony Lindgren
2010-05-07 18:28 ` Matthew Garrett
2010-05-07 18:43 ` Tony Lindgren
2010-05-07 18:46 ` Matthew Garrett
2010-05-07 19:06 ` Daniel Walker
2010-05-07 19:28 ` Tony Lindgren
2010-05-07 19:33 ` Matthew Garrett
2010-05-07 19:55 ` Tony Lindgren
2010-05-07 20:28 ` Matthew Garrett
2010-05-07 20:53 ` Tony Lindgren
2010-05-07 21:03 ` Matthew Garrett
2010-05-07 21:25 ` Tony Lindgren
2010-05-07 21:32 ` Arve Hjønnevåg
2010-05-07 21:39 ` Matthew Garrett
2010-05-07 21:42 ` Tony Lindgren
2010-05-07 21:48 ` Matthew Garrett
2010-05-07 22:00 ` Tony Lindgren
2010-05-07 22:28 ` Matthew Garrett
2010-05-07 21:30 ` Daniel Walker
2010-05-07 21:35 ` Arve Hjønnevåg
2010-05-07 21:43 ` Daniel Walker
2010-05-07 21:38 ` Matthew Garrett
2010-05-06 18:47 ` Alan Stern
2010-05-07 2:20 ` Tony Lindgren
2010-05-28 13:29 ` Pavel Machek
2010-05-28 13:42 ` Brian Swetland
2010-05-06 17:35 ` Daniel Walker
2010-05-06 18:36 ` Tony Lindgren
2010-05-06 19:11 ` Daniel Walker
2010-05-07 2:00 ` Tony Lindgren
2010-05-07 17:20 ` Daniel Walker
2010-05-07 17:36 ` Matthew Garrett
2010-05-07 17:40 ` Daniel Walker
2010-05-07 17:51 ` Matthew Garrett
2010-05-07 18:00 ` Daniel Walker
2010-05-07 18:17 ` Tony Lindgren
2010-05-07 17:50 ` Tony Lindgren
2010-05-07 3:45 ` mgross
2010-05-07 3:45 ` mgross
2010-05-07 4:10 ` Arve Hjønnevåg
2010-05-04 20:40 ` Arve Hjønnevåg
2010-05-03 16:40 ` [PATCH 0/8] Suspend block api (version 6) Kevin Hilman
2010-05-03 17:12 ` Alan Stern
2010-05-03 18:17 ` Kevin Hilman
2010-05-03 18:07 ` Mark Brown
2010-05-03 21:18 ` Rafael J. Wysocki
2010-05-03 23:37 ` Kevin Hilman
2010-05-04 0:09 ` Arve Hjønnevåg
2010-05-04 0:43 ` Brian Swetland
2010-05-04 13:59 ` Mark Brown
2010-05-04 18:06 ` Kevin Hilman
2010-05-04 19:06 ` Mark Brown
2010-05-04 20:37 ` Rafael J. Wysocki
2010-05-04 23:14 ` Kevin Hilman
2010-05-04 23:42 ` Rafael J. Wysocki
2010-05-04 20:23 ` Rafael J. Wysocki
2010-05-04 20:44 ` Rafael J. Wysocki
2010-05-04 23:56 ` Mark Brown
2010-05-05 0:22 ` Rafael J. Wysocki
2010-05-05 1:11 ` Brian Swetland
2010-05-05 11:06 ` Mark Brown
2010-05-05 12:00 ` Brian Swetland
2010-05-05 13:56 ` Mark Brown
2010-05-05 17:33 ` Matthew Garrett
2010-05-05 18:36 ` Alan Stern
2010-05-05 18:52 ` Matthew Garrett
2010-05-05 19:13 ` Alan Stern
2010-05-05 19:22 ` Matthew Garrett
2010-05-05 19:52 ` Mark Brown
2010-05-05 19:55 ` tytso
2010-05-05 20:26 ` Mark Brown
2010-05-05 20:44 ` Rafael J. Wysocki
2010-05-05 21:57 ` Mark Brown
2010-05-05 22:03 ` Brian Swetland
2010-05-05 22:05 ` Rafael J. Wysocki
2010-05-05 23:09 ` Mark Brown
2010-05-05 23:33 ` Rafael J. Wysocki
2010-05-06 0:21 ` Mark Brown
2010-05-06 0:51 ` Rafael J. Wysocki
2010-05-05 20:02 ` Matthew Garrett
2010-05-05 20:09 ` Mark Brown
2010-05-05 19:39 ` Mark Brown
2010-05-05 20:56 ` Brian Swetland
2010-05-05 23:40 ` Mark Brown
2010-05-06 4:25 ` Arve Hjønnevåg
2010-05-07 10:04 ` Mark Brown
2010-05-07 10:57 ` Arve Hjønnevåg
2010-05-07 11:21 ` Mark Brown
2010-05-07 11:29 ` Theodore Tso
2010-05-07 12:25 ` Mark Brown
2010-05-07 12:37 ` Brian Swetland
2010-05-07 13:30 ` Mark Brown
2010-05-11 18:47 ` Mark Brown
2010-05-07 11:41 ` Arve Hjønnevåg
2010-05-07 14:00 ` Mark Brown
2010-05-05 19:07 ` Mark Brown
2010-05-05 19:20 ` Alan Stern
2010-05-05 19:28 ` Matthew Garrett
2010-05-05 20:04 ` Alan Stern
2010-05-05 20:15 ` Mark Brown
2010-05-05 20:28 ` Rafael J. Wysocki
2010-05-05 23:03 ` Kevin Hilman
2010-05-05 23:16 ` Rafael J. Wysocki
2010-05-05 23:42 ` Brian Swetland
2010-05-06 14:08 ` Alan Stern
2010-05-06 19:26 ` Rafael J. Wysocki
2010-05-05 18:39 ` Mark Brown
2010-05-05 15:35 ` Alan Stern
2010-05-05 16:27 ` Mark Brown
2010-05-04 18:04 ` Kevin Hilman
2010-05-04 0:43 ` Matthew Garrett
2010-05-04 13:51 ` Alan Stern
2010-05-04 14:53 ` Mark Brown
2010-05-04 15:13 ` Kevin Hilman
2010-05-04 15:27 ` Matthew Garrett
2010-05-06 1:40 ` Magnus Damm
2010-05-04 15:13 ` Kevin Hilman
2010-05-04 15:28 ` Matthew Garrett
2010-05-03 21:50 ` Matthew Garrett
[not found] ` <alpine.DEB.2.00.1005141408260.3348@utopia.booyaka.com>
[not found] ` <20100514203202.GA12409@srcf.ucam.org>
[not found] ` <87aas2azc5.fsf@deeprootsystems.com>
[not found] ` <20100514231510.GG16989@thunk.org>
[not found] ` <87r5laa4oc.fsf@deeprootsystems.com>
[not found] ` <AANLkTilL90pYVlquvMDAEPHj_AraEi9Qzk-0tTjw9Bkx@mail.gmail.com>
2010-05-17 20:07 ` [linux-pm] " Mike Chan
2010-05-17 20:17 ` Vitaly Wool
2010-05-17 21:04 ` Mike Chan
2010-05-17 22:55 ` Kevin Hilman
2010-05-17 23:04 ` Brian Swetland
2010-05-24 18:57 ` Pavel Machek
2010-05-24 19:08 ` Matthew Garrett
2010-05-25 1:16 ` Arve Hjønnevåg
2010-05-26 17:32 ` Pavel Machek
2010-05-05 20:35 ` mark gross
2010-05-10 18:06 ` Kevin Hilman
2010-05-10 20:25 ` Rafael J. Wysocki
2010-05-11 16:12 ` Tony Lindgren
2010-05-11 16:14 ` Matthew Garrett
2010-05-11 16:36 ` Tony Lindgren
2010-05-11 16:45 ` Matthew Garrett
2010-05-11 16:58 ` Tony Lindgren
2010-05-11 17:03 ` Matthew Garrett
2010-05-11 17:24 ` Tony Lindgren
2010-05-11 17:30 ` Matthew Garrett
2010-05-11 17:48 ` Tony Lindgren
2010-05-11 18:01 ` Matthew Garrett
2010-05-11 18:19 ` Rafael J. Wysocki
2010-05-12 1:11 ` Arve Hjønnevåg
2010-05-12 11:22 ` Mark Brown
2010-05-13 3:35 ` [linux-pm] " Paul Walmsley
2010-05-13 12:17 ` Matthew Garrett
2010-05-13 17:33 ` Daniel Walker
2010-05-13 18:17 ` Brian Swetland
2010-05-13 18:25 ` Daniel Walker
2010-05-13 18:36 ` Matthew Garrett
2010-05-13 18:59 ` Daniel Walker
2010-05-13 19:11 ` Matthew Garrett
2010-05-13 19:36 ` Daniel Walker
2010-05-13 19:48 ` Matthew Garrett
2010-05-13 21:11 ` Rafael J. Wysocki
2010-05-13 21:16 ` Daniel Walker
2010-05-13 21:27 ` Rafael J. Wysocki
2010-05-13 21:33 ` Daniel Walker
2010-05-13 21:36 ` Tony Lindgren
2010-05-13 21:54 ` Rafael J. Wysocki
2010-05-13 21:46 ` Greg KH
2010-05-13 22:27 ` Mark Brown
2010-05-13 22:45 ` Greg KH
2010-05-14 0:03 ` Mark Brown
2010-05-13 22:46 ` Rafael J. Wysocki
2010-05-13 23:36 ` Mark Brown
2010-05-13 23:48 ` Brian Swetland
2010-05-14 0:29 ` Mark Brown
2010-05-13 22:33 ` Woodruff, Richard
2010-05-13 22:46 ` Greg KH
2010-05-13 23:06 ` Arve Hjønnevåg
2010-05-13 23:28 ` Brian Swetland
2010-05-14 16:47 ` Daniel Walker
2010-05-13 14:16 ` Alan Stern
2010-05-13 19:17 ` Tony Lindgren
2010-05-13 19:25 ` Matthew Garrett
2010-05-13 19:42 ` Tony Lindgren
2010-05-13 19:53 ` Matthew Garrett
2010-05-13 20:00 ` Tony Lindgren
2010-05-13 20:08 ` Matthew Garrett
2010-05-13 20:23 ` Tony Lindgren
2010-05-13 20:34 ` Matthew Garrett
2010-05-13 21:10 ` Tony Lindgren
2010-05-13 21:21 ` Matthew Garrett
2010-05-13 21:34 ` Tony Lindgren
2010-05-15 19:54 ` Matthew Garrett [this message]
2010-05-13 21:21 ` Rafael J. Wysocki
2010-05-13 21:25 ` Tony Lindgren
2010-05-13 21:56 ` Rafael J. Wysocki
2010-05-14 20:41 ` Kevin Hilman
2010-05-14 21:25 ` Rafael J. Wysocki
2010-05-14 21:40 ` Kevin Hilman
2010-05-14 21:50 ` Rafael J. Wysocki
2010-05-14 22:45 ` Kevin Hilman
2010-05-14 22:59 ` Brian Swetland
2010-05-15 2:58 ` Alan Stern
2010-05-15 3:40 ` Brian Swetland
2010-05-15 21:19 ` Alan Stern
2010-05-17 15:40 ` Kevin Hilman
2010-05-17 17:04 ` James Bottomley
2010-05-17 17:47 ` Felipe Balbi
2010-05-17 17:58 ` Matthew Garrett
2010-05-17 18:16 ` Felipe Balbi
2010-05-17 17:59 ` James Bottomley
2010-05-17 18:12 ` Felipe Balbi
2010-05-17 18:26 ` Brian Swetland
2010-05-17 18:39 ` Felipe Balbi
2010-05-17 18:45 ` Brian Swetland
2010-05-17 20:22 ` Rafael J. Wysocki
2010-05-17 18:45 ` Mark Brown
2010-05-17 18:47 ` Mike Chan
2010-05-17 19:24 ` James Bottomley
2010-05-17 19:38 ` Felipe Balbi
2010-05-17 19:39 ` Felipe Balbi
2010-05-17 19:49 ` James Bottomley
2010-05-18 6:40 ` Felipe Balbi
2010-05-18 13:59 ` James Bottomley
2010-05-19 6:59 ` Felipe Balbi
2010-05-19 20:42 ` Rafael J. Wysocki
2010-05-20 4:49 ` Felipe Balbi
2010-05-20 11:27 ` Vladimir Pantelic
2010-05-20 11:29 ` Felipe Balbi
2010-05-20 17:40 ` David Brownell
2010-05-20 18:50 ` Felipe Balbi
2010-05-20 23:08 ` David Brownell
2010-05-20 5:15 ` Florian Mickler
2010-05-20 8:57 ` Felipe Balbi
2010-05-20 8:57 ` Felipe Balbi
2010-05-20 10:05 ` Florian Mickler
2010-05-20 10:15 ` Felipe Balbi
2010-05-17 18:54 ` Kevin Hilman
2010-05-17 17:57 ` Daniel Walker
2010-05-15 20:14 ` Rafael J. Wysocki
2010-05-16 19:44 ` Mark Brown
2010-05-13 22:24 ` tytso
2010-05-13 20:36 ` Daniel Walker
2010-05-14 16:06 ` Kevin Hilman
2010-05-24 21:25 ` Pavel Machek
2010-05-13 21:41 ` Alan Stern
2010-05-13 21:54 ` Tony Lindgren
2010-05-13 22:07 ` Rafael J. Wysocki
2010-05-13 22:26 ` Arve Hjønnevåg
2010-05-13 21:14 ` Rafael J. Wysocki
2010-05-13 21:31 ` Tony Lindgren
2010-05-13 21:57 ` Rafael J. Wysocki
2010-05-13 21:37 ` Alan Stern
2010-05-13 21:47 ` Tony Lindgren
2010-05-13 22:01 ` Alan Stern
2010-05-13 22:08 ` Tony Lindgren
2010-05-13 22:28 ` Rafael J. Wysocki
2010-05-15 2:35 ` Alan Stern
2010-05-15 4:04 ` Arve Hjønnevåg
2010-05-13 22:04 ` Rafael J. Wysocki
2010-05-14 3:25 ` Magnus Damm
2010-05-14 16:18 ` Kevin Hilman
2010-05-15 2:47 ` Alan Stern
2010-05-24 21:24 ` Pavel Machek
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