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From: Simon Kirby <sim@hostway.ca>
To: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org,
	Vaughan Cao <vaughan.cao@oracle.com>
Subject: [3.12-rc] sg_open: leaving the kernel with locks still held!
Date: Tue, 22 Oct 2013 13:56:08 -0700	[thread overview]
Message-ID: <20131022205608.GA6616@hostway.ca> (raw)

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

Simon-

             reply	other threads:[~2013-10-22 21:16 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-10-22 20:56 Simon Kirby [this message]
2013-10-23  0:41 ` [3.12-rc] sg_open: leaving the kernel with locks still held! Douglas Gilbert
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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