From mboxrd@z Thu Jan 1 00:00:00 1970 From: Li Zefan Subject: Re: 3.5-rc3: BUG: Dentry still in use (1) [unmount of cgroup cgroup] Date: Thu, 28 Jun 2012 14:07:28 +0800 Message-ID: <4FEBF4A0.3040303@huawei.com> References: <20120627182903.GP15811@google.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20120627182903.GP15811@google.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: Content-Type: text/plain; charset="us-ascii" To: "tj@kernel.org" Cc: shyju pv , "linux-kernel@vger.kernel.org" , "cgroups@vger.kernel.org" , Sanil kumar , Masanari Iida tj@kernel.org wrote: > On Sun, Jun 24, 2012 at 07:08:07PM +0000, shyju pv wrote: >> Hi, >> Observed a crash on 3.5-rc3 with cgroup tests from LTP(Stable April,2012 release)on Dell Inspiron 1526[Intel(R) Core2Duo T7250, MEM 4GB] and also on another x86 quad core target(4GB RAM). >> LTP test case: cgroup_regression_test.sh(test 4,7 and 9 crashes randomly when the test cases are executed in order) I wrote thoese test scripts. ;) >> Shyju >> >> [ 532.805905] BUG: Dentry ffff8801164db490{i=491b,n=/} still in use (1) [unmount of cgroup cgrou > > Hmm... fa980ca87d "cgroup: superblock can't be released with active > dentries" is supposed to have fixed that. Looking into it. > I think I know what happened here: umount deativate_super(sb) dput(subdir) subdir->d_count-- d_release(subdir) deactivate_super(sb) shrink_dcache_for_umount(sb) BUG(root->d_count)!! root->d_count-- I use this script to reproduce the bug: mount -t cgroup -o cpu xxx /mnt mkdir /mnt/sub sleep 100 < /mnt/sub & kill $! wait $! umount /mnt