From mboxrd@z Thu Jan 1 00:00:00 1970 From: Simon Kirby Subject: [3.12-rc] sg_open: leaving the kernel with locks still held! Date: Tue, 22 Oct 2013 13:56:08 -0700 Message-ID: <20131022205608.GA6616@hostway.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org To: linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org, Vaughan Cao List-Id: linux-scsi@vger.kernel.org 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: [] 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-