From: Chris Mason <clm@fb.com>
To: Marc MERLIN <marc@merlins.org>
Cc: <linux-btrfs@vger.kernel.org>
Subject: Re: 3.16.2 btrfs deadlock
Date: Tue, 7 Oct 2014 17:22:52 -0400 [thread overview]
Message-ID: <1412716972.2374.1@mail.thefacebook.com> (raw)
In-Reply-To: <20141005202937.GK10696@merlins.org>
On Sun, Oct 5, 2014 at 4:29 PM, Marc MERLIN <marc@merlins.org> wrote:
> Deadlocks have been less frequent (good), but here is one.
>
> An rsync from 5 days ago got stuck on btrfs it seems, and things just
> started piling up on top until the system deadlocked
>
> I see btrfs-transaction saying wait on page, but if it's RAM, I had
> plenty left:
> total used free shared buffers
> cached
> Mem: 7894580 6950108 944472 0 40
> 4816148
> -/+ buffers/cache: 2133920 5760660
> Swap: 15616764 767004 14849760
>
>
> Here's the trace:
> SysRq : Show Blocked State
> task PC stack pid father
> md8_raid5 D ffff88017028cb80 0 675 2 0x00000000
> ffff88020fd67aa8 0000000000000046 ffffffff812f1799 ffff88020fd67fd8
> ffff880037228410 00000000000140c0 ffff88021e3940c0 ffff880037228410
> ffff8801f5579bf0 0000000000000004 ffff880211ad07c8 ffff88020fd67ab8
> Call Trace:
> [<ffffffff812f1799>] ? blk_flush_plug_list+0x1bc/0x1cb
> [<ffffffff8163a889>] schedule+0x6e/0x70
> [<ffffffff8163aa2b>] io_schedule+0x60/0x7a
> [<ffffffff812ef8f6>] get_request+0x4b8/0x56a
> [<ffffffff8130ba01>] ? cfq_merge+0x49/0x9e
> [<ffffffff81087b70>] ? finish_wait+0x65/0x65
> [<ffffffff812f1921>] blk_queue_bio+0x179/0x262
> [<ffffffff812eec2c>] generic_make_request+0x9c/0xdb
> [<ffffffffc042b31d>] handle_stripe+0x1e41/0x2166 [raid456]
> [<ffffffff81017316>] ? ___preempt_schedule+0x56/0xa8
> [<ffffffff8163d0d9>] ? _raw_spin_unlock_irqrestore+0x1f/0x32
> [<ffffffffc042b925>] handle_active_stripes.isra.22+0x2e3/0x359
> [raid456]
> [<ffffffff8151d35e>] ? md_wakeup_thread+0x55/0x58
> [<ffffffffc042bdd6>] raid5d+0x330/0x428 [raid456]
> [<ffffffff810795b1>] ? get_parent_ip+0xd/0x3c
> [<ffffffff815202f9>] md_thread+0x11c/0x13a
> [<ffffffff81087b70>] ? finish_wait+0x65/0x65
> [<ffffffff815201dd>] ? bb_store+0x55/0x55
> [<ffffffff8106e3a9>] kthread+0xae/0xb6
> [<ffffffff8106e2fb>] ? __kthread_parkme+0x61/0x61
> [<ffffffff8163d8fc>] ret_from_fork+0x7c/0xb0
> [<ffffffff8106e2fb>] ? __kthread_parkme+0x61/0x61
This trace shows we're stuck somewhere different from the 3.15 stalls.
md is waiting for a request, and unfortunately those are outside of
btrfs completely. It's likely that if you had let it sit, the box
would have eventually dig its way out.
-chris
next prev parent reply other threads:[~2014-10-07 21:23 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-10-05 20:29 3.16.2 btrfs deadlock Marc MERLIN
2014-10-05 23:16 ` 3.16.2 btrfs deadlock -> detecting deadlocks with cron Marc MERLIN
2014-10-07 21:22 ` Chris Mason [this message]
2014-10-07 23:45 ` 3.16.2 btrfs deadlock Marc MERLIN
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