From: Andrew Morton <akpm@osdl.org>
To: Nick Piggin <npiggin@suse.de>, Hugh Dickins <hugh@veritas.com>,
Linux Kernel <linux-kernel@vger.kernel.org>,
Linux Filesystems <linux-fsdevel@vger.kernel.org>,
Linux Memory Management <linux-mm@kvack.org>
Subject: Re: [patch 0/9] buffered write deadlock fix
Date: Tue, 30 Jan 2007 15:21:19 -0800 [thread overview]
Message-ID: <20070130152119.e0a18e58.akpm@osdl.org> (raw)
In-Reply-To: <20070130125558.ae9119b0.akpm@osdl.org>
On Tue, 30 Jan 2007 12:55:58 -0800
Andrew Morton <akpm@osdl.org> wrote:
> y'know, four or five years back I fixed this bug by doing
>
> current->locked_page = page;
>
> in the write() code, and then teaching the pagefault code to avoid locking
> the same page. Patch below.
>
> But then evil mean Hugh pointed out that the patch is still vulnerable to
> ab/ba deadlocking so I dropped it.
And he was right, of course. Task A holds file a's i_mutex and takes a
fault against file b's page. Task B holds file b's i_mutex and takes a
fault against file a's page. Drat.
I wonder if there's a sane way of preventing that.
next prev parent reply other threads:[~2007-01-30 23:21 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-29 10:31 [patch 0/9] buffered write deadlock fix Nick Piggin
2007-01-29 10:31 ` [patch 1/9] fs: libfs buffered write leak fix Nick Piggin
2007-02-02 23:52 ` Andrew Morton
2007-02-03 1:33 ` Nick Piggin
2007-02-03 1:58 ` Andrew Morton
2007-02-03 2:09 ` Nick Piggin
2007-02-03 2:19 ` Andrew Morton
2007-02-03 2:28 ` Nick Piggin
2007-02-03 17:49 ` Jörn Engel
2007-02-04 3:55 ` Nick Piggin
2007-01-29 10:31 ` [patch 2/9] mm: revert "generic_file_buffered_write(): handle zero length iovec segments" Nick Piggin
2007-01-29 10:32 ` [patch 3/9] mm: revert "generic_file_buffered_write(): deadlock on vectored write" Nick Piggin
2007-01-29 10:32 ` [patch 4/9] mm: generic_file_buffered_write cleanup Nick Piggin
2007-01-29 10:32 ` [patch 5/9] mm: debug write deadlocks Nick Piggin
2007-01-29 10:32 ` [patch 6/9] mm: be sure to trim blocks Nick Piggin
2007-01-29 10:32 ` [patch 7/9] mm: cleanup pagecache insertion operations Nick Piggin
2007-01-29 10:32 ` [patch 8/9] mm: generic_file_buffered_write iovec cleanup Nick Piggin
2007-01-29 10:33 ` [patch 9/9] mm: fix pagecache write deadlocks Nick Piggin
2007-01-29 11:11 ` Nick Piggin
2007-02-02 23:53 ` Andrew Morton
2007-02-03 1:38 ` Nick Piggin
2007-01-30 20:55 ` [patch 0/9] buffered write deadlock fix Andrew Morton
2007-01-30 23:21 ` Andrew Morton [this message]
2007-01-31 1:31 ` Nick Piggin
2007-01-31 0:32 ` Nick Piggin
2007-02-02 23:52 ` Andrew Morton
2007-02-03 1:22 ` Nick Piggin
2007-02-03 6:43 ` Suparna Bhattacharya
[not found] ` <20070203153145.GA3980@mail.ustc.edu.cn>
2007-02-03 15:31 ` Fengguang Wu
2007-02-03 15:31 ` Fengguang Wu
-- strict thread matches above, loose matches on Subject: below --
2007-02-04 8:49 Nick Piggin
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