From: "Stéphane Lesimple" <stephane_btrfs@lesimple.fr>
To: Qu Wenruo <quwenruo@cn.fujitsu.com>
Cc: linux-btrfs@vger.kernel.org
Subject: Re: [PATCH 0/2] Btrfs: Fix a insane extent_buffer copy behavior for qgroup
Date: Sat, 26 Sep 2015 00:35:48 +0200 [thread overview]
Message-ID: <eb99c836513f7d88542f078a1b095d83@all.all> (raw)
In-Reply-To: <1443148681-3015-1-git-send-email-quwenruo@cn.fujitsu.com>
Le 2015-09-25 04:37, Qu Wenruo a écrit :
> Stephane Lesimple reported an qgroup rescan bug:
>
> [92098.841309] general protection fault: 0000 [#1] SMP
> [92098.841338] Modules linked in: ...
> [92098.841814] CPU: 1 PID: 24655 Comm: kworker/u4:12 Not tainted
> 4.3.0-rc1 #1
> [92098.841868] Workqueue: btrfs-qgroup-rescan
> btrfs_qgroup_rescan_helper
> [btrfs]
> [92098.842261] Call Trace:
> [92098.842277] [<ffffffffc035a5d8>] ? read_extent_buffer+0xb8/0x110
> [btrfs]
> [92098.842304] [<ffffffffc0396d00>] ? btrfs_find_all_roots+0x60/0x70
> [btrfs]
> [92098.842329] [<ffffffffc039af3d>]
> btrfs_qgroup_rescan_worker+0x28d/0x5a0 [btrfs]
> ...
>
> The triggering function btrfs_disk_key_to_cpu(), which should never
> fail.
> But it turned out that the extent_buffere being called on is memcpied
> from an existing one.
>
> Such behavior to copy a structure with page pointers and locks in it is
> never a sane thing.
>
> Fix it by do it in memory other than extent_buffer.
>
> Qu Wenruo (2):
> btrfs: Add support to do stack item key operation
> btrfs: qgroup: Don't copy extent buffer to do qgroup rescan
>
> fs/btrfs/ctree.h | 20 ++++++++++++++++++++
> fs/btrfs/qgroup.c | 22 ++++++++++++----------
> 2 files changed, 32 insertions(+), 10 deletions(-)
I applied this patch and ran 100+ rescans on my filesystem for several
hours. No crash happened, where only a few rescans were enough to
trigger the bug previously.
I'm confident this patch fixes the GPF, thanks Qu !
--
Stéphane.
prev parent reply other threads:[~2015-09-25 22:35 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-25 2:37 [PATCH 0/2] Btrfs: Fix a insane extent_buffer copy behavior for qgroup Qu Wenruo
2015-09-25 2:38 ` [PATCH 1/2] btrfs: Add support to do stack item key operation Qu Wenruo
2015-10-01 16:46 ` David Sterba
2015-10-02 1:08 ` Qu Wenruo
2015-09-25 2:38 ` [PATCH 2/2] btrfs: qgroup: Don't copy extent buffer to do qgroup rescan Qu Wenruo
2015-09-25 22:35 ` Stéphane Lesimple [this message]
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