From: Douglas Gilbert <dgilbert@interlog.com>
To: Simon Kirby <sim@hostway.ca>,
linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
Vaughan Cao <vaughan.cao@oracle.com>
Subject: Re: [3.12-rc] sg_open: leaving the kernel with locks still held!
Date: Tue, 22 Oct 2013 20:41:34 -0400 [thread overview]
Message-ID: <52671B3E.6070804@interlog.com> (raw)
In-Reply-To: <20131022205608.GA6616@hostway.ca>
On 13-10-22 04:56 PM, Simon Kirby wrote:
> Hello!
>
> While trying to figure out why the request queue to sda (ext4) was
> clogging up on one of our btrfs backup boxes, I noticed a megarc process
> in D state, so enabled locking debugging, and got this (on 3.12-rc6):
>
> [ 205.372823] ================================================
> [ 205.372901] [ BUG: lock held when returning to user space! ]
> [ 205.372979] 3.12.0-rc6-hw-debug-pagealloc+ #67 Not tainted
> [ 205.373055] ------------------------------------------------
> [ 205.373132] megarc.bin/5283 is leaving the kernel with locks still held!
> [ 205.373212] 1 lock held by megarc.bin/5283:
> [ 205.373285] #0: (&sdp->o_sem){.+.+..}, at: [<ffffffff8161e650>] sg_open+0x3a0/0x4d0
>
> Vaughan, it seems you touched this area last in 15b06f9a02406e, and git
> tag --contains says this went in for 3.12-rc. We didn't see this on 3.11,
> though I haven't tried with lockdep.
>
> This is caused by some of our internal RAID monitoring scripts that run
> "megarc.bin -dispCfg -a0" (even though that controller isn't present on
> this server -- a PowerEdge 2950 w/Perc 5).
>
> strace output of the program execution that causes the above message is
> here: http://0x.ca/sim/ref/3.12-rc6/megarc_strace.txt
This has been reported. That patch will be reverted or,
if there is enough time, a fix will (or at least should)
go in before the release of lk 3.12 .
See this thread:
http://marc.info/?t=138228547300001&r=1&w=2
And you might test the patch and confirm that it does
fix the problem (and report back).
Doug Gilbert
next prev parent reply other threads:[~2013-10-23 0:41 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-22 20:56 [3.12-rc] sg_open: leaving the kernel with locks still held! Simon Kirby
2013-10-23 0:41 ` Douglas Gilbert [this message]
2013-10-23 7:44 ` James Bottomley
2013-10-23 12:11 ` Josh Boyer
2013-10-23 12:22 ` James Bottomley
2013-10-23 14:10 ` Douglas Gilbert
2013-10-25 0:37 ` Simon Kirby
2013-10-25 7:20 ` James Bottomley
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