From: Rik van Riel <riel@redhat.com>
To: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: fix hang on anon_vma->root->lock
Date: Thu, 26 Aug 2010 09:32:07 -0400 [thread overview]
Message-ID: <4C766CD7.8000004@redhat.com> (raw)
In-Reply-To: <alpine.LSU.2.00.1008252305540.19107@sister.anvils>
On 08/26/2010 02:12 AM, Hugh Dickins wrote:
> After several hours, kbuild tests hang with anon_vma_prepare() spinning on
> a newly allocated anon_vma's lock - on a box with CONFIG_TREE_PREEMPT_RCU=y
> (which makes this very much more likely, but it could happen without).
>
> The ever-subtle page_lock_anon_vma() now needs a further twist: since
> anon_vma_prepare() and anon_vma_fork() are liable to change the ->root
> of a reused anon_vma structure at any moment, page_lock_anon_vma()
> needs to check page_mapped() again before succeeding, otherwise
> page_unlock_anon_vma() might address a different root->lock.
>
> Signed-off-by: Hugh Dickins<hughd@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
And yes, AFAIK this code lived just in -mm up to now.
--
All rights reversed
WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com>
To: Hugh Dickins <hughd@google.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: fix hang on anon_vma->root->lock
Date: Thu, 26 Aug 2010 09:32:07 -0400 [thread overview]
Message-ID: <4C766CD7.8000004@redhat.com> (raw)
In-Reply-To: <alpine.LSU.2.00.1008252305540.19107@sister.anvils>
On 08/26/2010 02:12 AM, Hugh Dickins wrote:
> After several hours, kbuild tests hang with anon_vma_prepare() spinning on
> a newly allocated anon_vma's lock - on a box with CONFIG_TREE_PREEMPT_RCU=y
> (which makes this very much more likely, but it could happen without).
>
> The ever-subtle page_lock_anon_vma() now needs a further twist: since
> anon_vma_prepare() and anon_vma_fork() are liable to change the ->root
> of a reused anon_vma structure at any moment, page_lock_anon_vma()
> needs to check page_mapped() again before succeeding, otherwise
> page_unlock_anon_vma() might address a different root->lock.
>
> Signed-off-by: Hugh Dickins<hughd@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
And yes, AFAIK this code lived just in -mm up to now.
--
All rights reversed
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next prev parent reply other threads:[~2010-08-26 13:32 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-08-26 6:12 [PATCH] mm: fix hang on anon_vma->root->lock Hugh Dickins
2010-08-26 6:12 ` Hugh Dickins
2010-08-26 6:41 ` David Miller
2010-08-26 6:41 ` David Miller
2010-08-26 10:54 ` Hugh Dickins
2010-08-26 10:54 ` Hugh Dickins
2010-08-26 19:00 ` David Miller
2010-08-26 19:00 ` David Miller
2010-08-27 0:19 ` Andrea Arcangeli
2010-08-27 0:19 ` Andrea Arcangeli
2010-08-26 13:32 ` Rik van Riel [this message]
2010-08-26 13:32 ` Rik van Riel
2010-08-26 23:50 ` Andrea Arcangeli
2010-08-26 23:50 ` Andrea Arcangeli
2010-08-27 1:43 ` Hugh Dickins
2010-08-27 1:43 ` Hugh Dickins
2010-08-27 9:55 ` Andrea Arcangeli
2010-08-27 9:55 ` Andrea Arcangeli
2010-08-27 16:43 ` Hugh Dickins
2010-08-27 16:43 ` Hugh Dickins
2010-08-27 17:13 ` Christoph Lameter
2010-08-27 17:13 ` Christoph Lameter
2010-08-27 17:55 ` Hugh Dickins
2010-08-27 17:55 ` Hugh Dickins
2010-08-27 19:29 ` Christoph Lameter
2010-08-27 19:29 ` Christoph Lameter
2010-08-27 20:14 ` Hugh Dickins
2010-08-27 20:14 ` Hugh Dickins
2010-08-27 20:56 ` Christoph Lameter
2010-08-27 20:56 ` Christoph Lameter
2010-08-27 21:28 ` Hugh Dickins
2010-08-27 21:28 ` Hugh Dickins
2010-08-27 21:33 ` Hugh Dickins
2010-08-27 21:33 ` Hugh Dickins
2010-08-27 23:06 ` Christoph Lameter
2010-08-27 23:06 ` Christoph Lameter
2010-08-28 1:07 ` Hugh Dickins
2010-08-28 1:07 ` Hugh Dickins
2010-08-28 2:47 ` Christoph Lameter
2010-08-28 2:47 ` Christoph Lameter
2010-08-28 10:17 ` Peter Zijlstra
2010-08-28 10:17 ` Peter Zijlstra
2010-08-28 15:54 ` Andrea Arcangeli
2010-08-28 15:54 ` Andrea Arcangeli
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