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From: Dave Kleikamp <dave.kleikamp@oracle.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"Rafael J. Wysocki" <rjw@sisk.pl>,
	jfs-discussion@lists.sourceforge.net,
	Kernel Testers List <kernel-testers@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Maciej Rutecki <maciej.rutecki@gmail.com>,
	Florian Mickler <florian@mickler.org>,
	davem@davemloft.net, Al Viro <viro@zeniv.linux.org.uk>,
	linux-mm@kvack.org
Subject: Re: [PATCH v2] vfs: __read_cache_page should use gfp argument rather than GFP_KERNEL
Date: Wed, 21 Dec 2011 14:53:44 -0600	[thread overview]
Message-ID: <4EF24758.5030704@oracle.com> (raw)
In-Reply-To: <20111221122843.18f673c7.akpm@linux-foundation.org>

On 12/21/2011 02:28 PM, Andrew Morton wrote:
> On Wed, 21 Dec 2011 11:05:48 -0600
> Dave Kleikamp <dave.kleikamp@oracle.com> wrote:
> 
>> [ updated to remove now-obsolete comment in read_cache_page_gfp()]
>>
>> lockdep reports a deadlock in jfs because a special inode's rw semaphore
>> is taken recursively. The mapping's gfp mask is GFP_NOFS, but is not used
>> when __read_cache_page() calls add_to_page_cache_lru().
> 
> Well hang on, it's not just a lockdep splat.  The kernel actually will
> deadlock if we reenter JFS via this GFP_KERNEL allocation attempt, yes?

Yes, it could result in a real deadlock.

> Was that GFP_NOFS allocation recently added to JFS?  If not then we
> should backport this deadlock fix into -stable, no?

Yes, that would make sense.

Shaggy

WARNING: multiple messages have this Message-ID (diff)
From: Dave Kleikamp <dave.kleikamp@oracle.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Hugh Dickins <hughd@google.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	"Rafael J. Wysocki" <rjw@sisk.pl>,
	jfs-discussion@lists.sourceforge.net,
	Kernel Testers List <kernel-testers@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Maciej Rutecki <maciej.rutecki@gmail.com>,
	Florian Mickler <florian@mickler.org>,
	davem@davemloft.net, Al Viro <viro@zeniv.linux.org.uk>,
	linux-mm@kvack.org
Subject: Re: [PATCH v2] vfs: __read_cache_page should use gfp argument rather than GFP_KERNEL
Date: Wed, 21 Dec 2011 14:53:44 -0600	[thread overview]
Message-ID: <4EF24758.5030704@oracle.com> (raw)
In-Reply-To: <20111221122843.18f673c7.akpm@linux-foundation.org>

On 12/21/2011 02:28 PM, Andrew Morton wrote:
> On Wed, 21 Dec 2011 11:05:48 -0600
> Dave Kleikamp <dave.kleikamp@oracle.com> wrote:
> 
>> [ updated to remove now-obsolete comment in read_cache_page_gfp()]
>>
>> lockdep reports a deadlock in jfs because a special inode's rw semaphore
>> is taken recursively. The mapping's gfp mask is GFP_NOFS, but is not used
>> when __read_cache_page() calls add_to_page_cache_lru().
> 
> Well hang on, it's not just a lockdep splat.  The kernel actually will
> deadlock if we reenter JFS via this GFP_KERNEL allocation attempt, yes?

Yes, it could result in a real deadlock.

> Was that GFP_NOFS allocation recently added to JFS?  If not then we
> should backport this deadlock fix into -stable, no?

Yes, that would make sense.

Shaggy

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  reply	other threads:[~2011-12-21 20:56 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-12-20 23:54 [Resend] 3.2-rc6+: Reported regressions from 3.0 and 3.1 Rafael J. Wysocki
2011-12-20 23:54 ` Rafael J. Wysocki
2011-12-21  2:31 ` Linus Torvalds
2011-12-21  2:31   ` Linus Torvalds
2011-12-21  4:23   ` Dave Kleikamp
2011-12-21  4:23     ` Dave Kleikamp
2011-12-21  4:44     ` Linus Torvalds
2011-12-21  4:44       ` Linus Torvalds
2011-12-21  4:44       ` Linus Torvalds
2011-12-21  6:15       ` Hugh Dickins
2011-12-21  7:10         ` Al Viro
2011-12-21  7:10           ` Al Viro
2011-12-21  7:10           ` Al Viro
2011-12-21 17:05         ` [PATCH v2] vfs: __read_cache_page should use gfp argument rather than GFP_KERNEL Dave Kleikamp
2011-12-21 17:05           ` Dave Kleikamp
2011-12-21 20:28           ` Andrew Morton
2011-12-21 20:28             ` Andrew Morton
2011-12-21 20:28             ` Andrew Morton
2011-12-21 20:53             ` Dave Kleikamp [this message]
2011-12-21 20:53               ` Dave Kleikamp
2011-12-21  4:50   ` [Resend] 3.2-rc6+: Reported regressions from 3.0 and 3.1 David Miller
2011-12-21  4:50     ` David Miller
2011-12-21 16:32 ` Nick Bowler
2011-12-21 16:32   ` Nick Bowler
2011-12-21 17:51   ` Keith Packard
2011-12-21 17:51     ` Keith Packard
2011-12-21 21:01 ` Jan Kara
2011-12-21 21:01   ` Jan Kara
2011-12-22 10:58 ` Srivatsa S. Bhat
2011-12-22 10:58   ` Srivatsa S. Bhat
2011-12-22 11:27   ` Jeff Layton
2011-12-22 11:27     ` Jeff Layton
2011-12-22 11:15 ` Srivatsa S. Bhat
2011-12-22 11:15   ` Srivatsa S. Bhat

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