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From: "Stephen C. Tweedie" <sct@redhat.com>
To: Linus Torvalds <torvalds@transmeta.com>
Cc: Savochkin Andrey Vladimirovich <saw@msu.ru>,
	Andrea Arcangeli <andrea@e-mind.com>,
	steve@netplus.net, "Eric W. Biederman" <ebiederm+eric@ccr.net>,
	brent verner <damonbrent@earthlink.net>,
	"Garst R. Reese" <reese@isn.net>,
	Kalle Andersson <kalle.andersson@mbox303.swipnet.se>,
	Zlatko Calusic <Zlatko.Calusic@CARNet.hr>,
	Ben McCann <bmccann@indusriver.com>,
	Alan Cox <alan@lxorguk.ukuu.org.uk>,
	bredelin@ucsd.edu, "Stephen C. Tweedie" <sct@redhat.com>,
	linux-kernel@vger.rutgers.edu,
	Rik van Riel <H.H.vanRiel@phys.uu.nl>,
	linux-mm@kvack.org
Subject: Re: MM deadlock [was: Re: arca-vm-8...]
Date: Sun, 10 Jan 1999 16:59:43 GMT	[thread overview]
Message-ID: <199901101659.QAA00922@dax.scot.redhat.com> (raw)
In-Reply-To: <Pine.LNX.3.95.990109134233.3478A-100000@penguin.transmeta.com>

Hi,

On Sat, 9 Jan 1999 13:50:14 -0800 (PST), Linus Torvalds
<torvalds@transmeta.com> said:

> On Sat, 9 Jan 1999, Linus Torvalds wrote:
>> 
>> The cleanest solution I can think of is actually to allow semaphores to be
>> recursive. I can do that with minimal overhead (just one extra instruction
>> in the non-contention case), so it's not too bad, and I've wanted to do it
>> for certain other things, but it's still a nasty piece of code to mess
>> around with. 

Ack.  I've been having a closer look, and making the superblock lock
recursive doesn't work: the ext2fs allocation code is definitely not
reentrant.  In particular, the bitmap buffers can get evicted out from
under our feet if we reenter the block allocation code, leading to nasty
filesystem and/or memory corruption.  The allocation code can also get
confused if the bitmap contents change between checking the group
descriptor for a block group and reading in the bitmap itself, leading
to potential ENOSPC errors turning up wrongly.

Preventing recursive VM access to the filesystem while we have the
superblock lock seems the only easy way out short of making the
allocation/truncate code fully reentrant.

On the other hand, it does look as if the inode deadlock is dealt with
OK if we just make that semaphore recursive; I can't see anywhere that
dies if we make that change.  This does somewhat imply that we may need
to make a distinction between reentrant and non-reentrant semaphores if
we go down this route.

--Stephen.
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  parent reply	other threads:[~1999-01-10 17:00 UTC|newest]

Thread overview: 243+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <199812290146.BAA12687@terrorserver.swansea.linux.org.uk>
1998-12-31 18:00 ` 2.2.0 Bug summary Andrea Arcangeli
1998-12-31 18:34   ` [patch] new-vm improvement [Re: 2.2.0 Bug summary] Andrea Arcangeli
1999-01-01  0:16     ` Steve Bergman
1999-01-01 17:16       ` Andrea Arcangeli
1999-01-01 16:44     ` Andrea Arcangeli
1999-01-01 20:02       ` Andrea Arcangeli
1999-01-01 23:46         ` Steve Bergman
1999-01-02  6:55           ` Linus Torvalds
1999-01-02  8:33             ` Steve Bergman
1999-01-02 14:48             ` Andrea Arcangeli
1999-01-02 15:38             ` Andrea Arcangeli
1999-01-02 18:10               ` Linus Torvalds
1999-01-02 20:52               ` Andrea Arcangeli
1999-01-03  2:59                 ` Andrea Arcangeli
1999-01-04 18:08                   ` [patch] arca-vm-6, killed kswapd [Re: [patch] new-vm improvement , [Re: 2.2.0 Bug summary]] Andrea Arcangeli
1999-01-04 20:56                     ` Linus Torvalds
1999-01-04 21:10                       ` Rik van Riel
1999-01-04 22:04                       ` Alan Cox
1999-01-04 21:55                         ` Linus Torvalds
1999-01-04 22:51                           ` Andrea Arcangeli
1999-01-05  0:32                             ` Andrea Arcangeli
1999-01-05  0:52                               ` Zlatko Calusic
1999-01-05  3:02                               ` Zlatko Calusic
1999-01-05 11:49                                 ` Andrea Arcangeli
1999-01-05 13:23                                   ` Zlatko Calusic
1999-01-05 15:42                                     ` Andrea Arcangeli
1999-01-05 16:16                                       ` Zlatko Calusic
1999-01-05 15:35                               ` arca-vm-8 [Re: [patch] arca-vm-6, killed kswapd [Re: [patch] new-vm , improvement , [Re: 2.2.0 Bug summary]]] Andrea Arcangeli
1999-01-06 14:48                                 ` Andrea Arcangeli
1999-01-06 23:31                                   ` Andrea Arcangeli
1999-01-07  3:32                                     ` Results: 2.2.0-pre5 vs arcavm10 vs arcavm9 vs arcavm7 Steve Bergman
1999-01-07 12:02                                       ` Andrea Arcangeli
1999-01-07 20:27                                         ` Linus Torvalds
1999-01-07 23:56                                           ` Andrea Arcangeli
1999-01-07 17:35                                       ` Linus Torvalds
1999-01-07 18:44                                         ` Zlatko Calusic
1999-01-07 19:33                                           ` Linus Torvalds
1999-01-07 21:10                                             ` Zlatko Calusic
1999-01-07 19:38                                           ` Zlatko Calusic
1999-01-07 19:40                                           ` Andrea Arcangeli
1999-01-09  6:28                                           ` 2.2.0-pre[56] swap performance poor with > 1 thrashing task Dax Kelson
1999-01-09  6:32                                             ` Zlatko Calusic
1999-01-09  6:44                                               ` Linus Torvalds
1999-01-09 18:58                                                 ` Andrea Arcangeli
1999-01-11  9:21                                                 ` Buffer handling (setting PG_referenced on access) Zlatko Calusic
1999-01-11 17:44                                                   ` Linus Torvalds
1999-01-11 20:14                                                     ` Zlatko Calusic
1999-01-16 17:35                                                 ` 2.2.0-pre[56] swap performance poor with > 1 thrashing task Andrea Arcangeli
1999-01-09  7:48                                             ` Benjamin Redelings I
1999-01-09  6:53                                               ` Linus Torvalds
1999-01-09 22:39                                       ` Results: pre6 vs pre6+zlatko's_patch vs pre5 vs arcavm13 Steve Bergman
1999-01-10  0:28                                         ` Steve Bergman
1999-01-10  5:35                                           ` Linus Torvalds
1999-01-10 18:33                                             ` Andrea Arcangeli
1999-01-10 18:43                                             ` Steve Bergman
1999-01-10 19:08                                               ` Linus Torvalds
1999-01-10 19:23                                                 ` Vladimir Dergachev
1999-01-10 20:09                                                 ` Andrea Arcangeli
1999-01-10 20:29                                                 ` Steve Bergman
1999-01-10 21:41                                                   ` Linus Torvalds
1999-01-10 23:33                                                     ` testing/pre-7 and do_poll() Chip Salzenberg
1999-01-11  6:02                                                       ` Linus Torvalds
1999-01-11  6:26                                                         ` Chip Salzenberg
1999-01-11  6:46                                                           ` Linus Torvalds
1999-01-11  6:59                                                             ` Chip Salzenberg
1999-01-11  7:02                                                               ` Linus Torvalds
1999-01-11 22:08                                                                 ` Shawn Leas
1999-01-11 22:13                                                                   ` Linus Torvalds
1999-01-12  0:25                                                                     ` estafford
1999-01-12  8:25                                                                       ` Shawn Leas
1999-01-12  7:06                                                                     ` Gregory Maxwell
1999-01-11 20:20                                                       ` Adam Heath
1999-01-11 16:57                                                   ` Results: pre6 vs pre6+zlatko's_patch vs pre5 vs arcavm13 Steve Bergman
1999-01-11 19:36                                                     ` Andrea Arcangeli
1999-01-11 23:03                                                       ` Andrea Arcangeli
1999-01-11 23:38                                                         ` Zlatko Calusic
1999-01-12  2:02                                                         ` Steve Bergman
1999-01-12  3:21                                                           ` Results: Zlatko's new vm patch Steve Bergman
1999-01-12  5:33                                                             ` Linus Torvalds
1999-01-12 14:49                                                               ` Andrea Arcangeli
1999-01-12 16:58                                                               ` Joseph Anthony
1999-01-12 18:16                                                                 ` Stephen C. Tweedie
1999-01-12 20:15                                                                   ` Michael K Vance
1999-01-13 19:25                                                                     ` Stephen C. Tweedie
1999-01-12 18:24                                                               ` Michael K Vance
1999-01-13  0:01                                                               ` Where to find pre7. Was: " Robert Thorncrantz
1999-01-13 20:47                                                             ` [patch] arca-vm-19 [Re: Results: Zlatko's new vm patch] Andrea Arcangeli
1999-01-14 12:30                                                               ` Andrea Arcangeli
1999-01-15 23:56                                                                 ` [patch] NEW: arca-vm-21, swapout via shrink_mmap using PG_dirty Andrea Arcangeli
1999-01-16 16:49                                                                   ` Andrea Arcangeli
1999-01-17 23:47                                                                     ` Andrea Arcangeli
1999-01-18  5:11                                                                       ` Linus Torvalds
1999-01-18  7:28                                                                         ` Eric W. Biederman
1999-01-18 10:00                                                                           ` Andrea Arcangeli
1999-01-18  9:15                                                                         ` Andrea Arcangeli
1999-01-18 17:49                                                                           ` Linus Torvalds
1999-01-18 19:22                                                                       ` Andrea Arcangeli
1999-01-10 20:40                                               ` Results: pre6 vs pre6+zlatko's_patch vs pre5 vs arcavm13 Andrea Arcangeli
1999-01-10 20:50                                                 ` Linus Torvalds
1999-01-10 21:01                                                   ` Andrea Arcangeli
1999-01-10 21:51                                                     ` Steve Bergman
1999-01-10 22:50                                                       ` Results: arcavm15, et. al Steve Bergman
1999-01-11  0:20                                                         ` Steve Bergman
1999-01-11 13:21                                                         ` Andrea Arcangeli
1999-01-11  3:47                                         ` Results: pre6 vs pre6+zlatko's_patch vs pre5 vs arcavm13 Gregory Maxwell
1999-01-06 23:35                                   ` arca-vm-8 [Re: [patch] arca-vm-6, killed kswapd [Re: [patch] new-vm , improvement , [Re: 2.2.0 Bug summary]]] Linus Torvalds
1999-01-07  4:30                                     ` Eric W. Biederman
1999-01-07 17:56                                       ` Linus Torvalds
1999-01-07 18:18                                         ` Rik van Riel
1999-01-07 19:19                                           ` arca-vm-8 [Re: [patch] arca-vm-6, killed kswapd [Re: [patch] Alan Cox
1999-01-07 18:55                                         ` arca-vm-8 [Re: [patch] arca-vm-6, killed kswapd [Re: [patch] new-vm , improvement , [Re: 2.2.0 Bug summary]]] Zlatko Calusic
1999-01-07 22:57                                         ` Linus Torvalds
1999-01-08  1:16                                           ` Linus Torvalds
1999-01-08 10:45                                             ` Andrea Arcangeli
1999-01-08 19:06                                               ` Linus Torvalds
1999-01-09  9:43                                           ` MM deadlock [was: Re: arca-vm-8...] Savochkin Andrey Vladimirovich
1999-01-09 18:00                                             ` Linus Torvalds
1999-01-09 18:41                                               ` Andrea Arcangeli
1999-01-10 21:41                                                 ` Stephen C. Tweedie
1999-01-10 21:47                                                   ` Linus Torvalds
1999-01-09 21:50                                               ` Linus Torvalds
1999-01-10 11:56                                                 ` Savochkin Andrey Vladimirovich
1999-01-10 17:59                                                   ` Andrea Arcangeli
1999-01-10 22:33                                                   ` Stephen C. Tweedie
1999-01-10 16:59                                                 ` Stephen C. Tweedie [this message]
1999-01-10 18:13                                                   ` Andrea Arcangeli
1999-01-10 18:35                                                   ` Linus Torvalds
1999-01-10 19:45                                                     ` Alan Cox
1999-01-10 19:03                                                       ` Andrea Arcangeli
1999-01-10 21:39                                                         ` Stephen C. Tweedie
1999-01-10 19:09                                                       ` Linus Torvalds
1999-01-10 20:33                                                         ` Alan Cox
1999-01-10 20:07                                                           ` Linus Torvalds
1999-01-10 22:18                                                     ` Stephen C. Tweedie
1999-01-10 22:49                                                     ` Stephen C. Tweedie
1999-01-11  6:04                                                       ` Eric W. Biederman
1999-01-12 16:06                                                         ` Stephen C. Tweedie
1999-01-12 17:54                                                           ` Linus Torvalds
1999-01-12 18:44                                                             ` Zlatko Calusic
1999-01-12 19:05                                                               ` Andrea Arcangeli
1999-01-13 17:48                                                                 ` Stephen C. Tweedie
1999-01-13 18:07                                                                   ` 2.2.0-pre6 ain't nice =( Kalle Andersson
1999-01-13 19:05                                                                   ` MM deadlock [was: Re: arca-vm-8...] Alan Cox
1999-01-13 19:23                                                                     ` MOLNAR Ingo
1999-01-13 19:26                                                                     ` Andrea Arcangeli
1999-01-14 11:02                                                                       ` Mike Jagdis
1999-01-14 22:38                                                                         ` Andrea Arcangeli
1999-01-15  7:40                                                                       ` Agus Budy Wuysang
1999-01-14 10:48                                                                   ` Mike Jagdis
1999-01-12 21:46                                                               ` Rik van Riel
1999-01-13  6:52                                                                 ` Zlatko Calusic
1999-01-13 13:45                                                                 ` Andrea Arcangeli
1999-01-13 13:58                                                                   ` Chris Evans
1999-01-13 15:07                                                                     ` Andrea Arcangeli
1999-01-13 22:11                                                                       ` Stephen C. Tweedie
1999-01-13 14:59                                                                   ` Rik van Riel
1999-01-13 18:10                                                                     ` Andrea Arcangeli
1999-01-13 22:14                                                                       ` Stephen C. Tweedie
1999-01-14 14:53                                                                         ` Dr. Werner Fink
1999-01-21 16:50                                                                           ` Stephen C. Tweedie
1999-01-21 19:53                                                                             ` Andrea Arcangeli
1999-01-22 13:55                                                                               ` Stephen C. Tweedie
1999-01-22 19:45                                                                                 ` Andrea Arcangeli
1999-01-23 23:20                                                                             ` Alan Cox
1999-01-24  0:19                                                                               ` Linus Torvalds
1999-01-24 18:33                                                                                 ` Gregory Maxwell
1999-01-25  0:21                                                                                   ` Linus Torvalds
1999-01-25  1:28                                                                                     ` Alan Cox
1999-01-25  3:35                                                                                       ` pmonta
1999-01-25  4:17                                                                                       ` Linus Torvalds
1999-01-24 20:33                                                                                 ` Alan Cox
1999-01-25  0:27                                                                                   ` Linus Torvalds
1999-01-25  1:38                                                                                     ` Alan Cox
1999-01-25  1:04                                                                                       ` Andrea Arcangeli
1999-01-25  2:10                                                                                         ` Alan Cox
1999-01-25  3:16                                                                                           ` Garst R. Reese
1999-01-25 10:49                                                                                             ` Alan Cox
1999-01-25 14:06                                                                                           ` Rik van Riel
1999-01-25 21:59                                                                                       ` Gerard Roudier
1999-01-26 11:45                                                                                         ` Thomas Sailer
1999-01-26 20:48                                                                                           ` Gerard Roudier
1999-01-26 21:24                                                                                             ` Thomas Sailer
1999-01-27  0:25                                                                                             ` David Lang
1999-01-27 16:05                                                                                             ` Stephen C. Tweedie
1999-01-27 20:11                                                                                               ` Gerard Roudier
1999-01-26 13:06                                                                                         ` Stephen C. Tweedie
1999-01-26 14:28                                                                                           ` Alan Cox
1999-01-26 14:15                                                                                             ` MOLNAR Ingo
1999-01-26 14:36                                                                                               ` yodaiken
1999-01-26 15:21                                                                                                 ` MOLNAR Ingo
1999-01-27 10:31                                                                                                   ` yodaiken
1999-01-26 15:46                                                                                                 ` Alan Cox
1999-01-26 16:45                                                                                                   ` Stephen C. Tweedie
1999-01-30  7:01                                                                                                     ` yodaiken
1999-02-01 13:07                                                                                                       ` Stephen C. Tweedie
1999-01-26 16:37                                                                                               ` Stephen C. Tweedie
1999-01-27 11:35                                                                                               ` Jakub Jelinek
1999-01-26 14:21                                                                                             ` Rik van Riel
1999-01-25 16:25                                                                                 ` Stephen C. Tweedie
1999-01-25 16:52                                                                                   ` Andrea Arcangeli
1999-01-25 18:27                                                                                   ` Linus Torvalds
1999-01-25 18:43                                                                                     ` Stephen C. Tweedie
1999-01-25 18:49                                                                                       ` Linus Torvalds
1999-01-25 18:43                                                                                   ` Linus Torvalds
1999-01-25 19:15                                                                                     ` Stephen C. Tweedie
1999-01-26  1:57                                                                                   ` Andrea Arcangeli
1999-01-26 18:37                                                                                     ` Andrea Arcangeli
1999-01-27 12:13                                                                                     ` Stephen C. Tweedie
1999-01-22 16:29                                                                           ` Eric W. Biederman
1999-01-25 13:14                                                                             ` Dr. Werner Fink
1999-01-25 17:56                                                                               ` Stephen C. Tweedie
1999-01-25 19:10                                                                               ` Andrea Arcangeli
1999-01-25 20:49                                                                                 ` Dr. Werner Fink
1999-01-25 20:56                                                                                   ` Linus Torvalds
1999-01-26 12:23                                                                                     ` Rik van Riel
1999-01-26 15:44                                                                                       ` Andrea Arcangeli
1999-01-27 14:52                                                                                   ` Stephen C. Tweedie
1999-01-28 19:12                                                                                     ` Dr. Werner Fink
1999-01-13 17:55                                                                   ` [PATCH] " Stephen C. Tweedie
1999-01-13 18:52                                                                     ` Andrea Arcangeli
1999-01-13 22:10                                                                       ` Stephen C. Tweedie
1999-01-13 22:30                                                                         ` Linus Torvalds
1999-01-11 11:20                                                       ` Pavel Machek
1999-01-11 17:35                                                         ` Stephen C. Tweedie
1999-01-11 14:11                                                     ` Savochkin Andrey Vladimirovich
1999-01-11 17:55                                                       ` Linus Torvalds
1999-01-11 18:37                                                         ` Andrea Arcangeli
1999-01-08  2:56                                         ` arca-vm-8 [Re: [patch] arca-vm-6, killed kswapd [Re: [patch] new-vm , improvement , [Re: 2.2.0 Bug summary]]] Eric W. Biederman
1999-01-09  0:50                                         ` David S. Miller
1999-01-09  2:13                                         ` Stephen C. Tweedie
1999-01-09  2:34                                           ` Andrea Arcangeli
1999-01-09  9:30                                             ` Stephen C. Tweedie
1999-01-09 12:11                                           ` Andrea Arcangeli
1999-01-07 14:11                                     ` Andrea Arcangeli
1999-01-07 18:19                                       ` Linus Torvalds
1999-01-07 20:35                                         ` Andrea Arcangeli
1999-01-07 23:51                                           ` Linus Torvalds
1999-01-08  0:04                                             ` Andrea Arcangeli
1999-01-04 22:43                         ` [patch] arca-vm-6, killed kswapd [Re: [patch] new-vm improvement , [Re: 2.2.0 Bug summary]] Andrea Arcangeli
1999-01-04 22:29                       ` Andrea Arcangeli
1999-01-05 13:33                   ` [patch] new-vm improvement [Re: 2.2.0 Bug summary] Ben McCann
1999-01-02 20:04             ` Steve Bergman
1999-01-02  3:03         ` Andrea Arcangeli

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