From: David Miller <davem@davemloft.net>
To: hughd@google.com
Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org,
riel@redhat.com, aarcange@redhat.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: fix hang on anon_vma->root->lock
Date: Wed, 25 Aug 2010 23:41:49 -0700 (PDT) [thread overview]
Message-ID: <20100825.234149.189710316.davem@davemloft.net> (raw)
In-Reply-To: <alpine.LSU.2.00.1008252305540.19107@sister.anvils>
From: Hugh Dickins <hughd@google.com>
Date: Wed, 25 Aug 2010 23:12:54 -0700 (PDT)
> 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>
Interesting, is the condition which allows this to trigger specific
to this merge window or was it always possible?
WARNING: multiple messages have this Message-ID (diff)
From: David Miller <davem@davemloft.net>
To: hughd@google.com
Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org,
riel@redhat.com, aarcange@redhat.com,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH] mm: fix hang on anon_vma->root->lock
Date: Wed, 25 Aug 2010 23:41:49 -0700 (PDT) [thread overview]
Message-ID: <20100825.234149.189710316.davem@davemloft.net> (raw)
In-Reply-To: <alpine.LSU.2.00.1008252305540.19107@sister.anvils>
From: Hugh Dickins <hughd@google.com>
Date: Wed, 25 Aug 2010 23:12:54 -0700 (PDT)
> 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>
Interesting, is the condition which allows this to trigger specific
to this merge window or was it always possible?
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2010-08-26 6:41 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 [this message]
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
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20100825.234149.189710316.davem@davemloft.net \
--to=davem@davemloft.net \
--cc=aarcange@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=hughd@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=riel@redhat.com \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.