From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grzegorz Nosek Subject: Re: BUG in tty_open when using containers and ptrace Date: Thu, 23 Jul 2009 00:25:50 +0200 Message-ID: <20090722222550.GA633@megiteam.pl> References: <20090713193058.GL18617@megiteam.pl> <20090713202610.GA6447@us.ibm.com> <20090713223444.GM18617@megiteam.pl> <20090714064905.GA25278@us.ibm.com> <20090714103129.GB12958@megiteam.pl> <20090715044744.GA25745@us.ibm.com> <20090715131923.GB21417@megiteam.pl> <20090718205244.GA23625@us.ibm.com> <20090719071531.GA20818@megiteam.pl> <20090722064120.GA24373@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20090722064120.GA24373-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: Sukadev Bhattiprolu Cc: containers-qjLDD68F18O7TbgM5vRIOg@public.gmane.org, Alan Cox , lxc-devel-5NWGOfrQmneRv+LV9MX5uipxlwaOVQ5f@public.gmane.org List-Id: containers.vger.kernel.org On wto, lip 21, 2009 at 11:41:20 -0700, Sukadev Bhattiprolu wrote: > I set > CONFIG_SLUB_DEBUG=y > CONFIG_SLUB=y > CONFIG_SLUB_DEBUG_ON=y > # CONFIG_SLUB_STATS is not set > > and tried 2.6.29, 2.6.31-rc3 and linux-mmotm from July 13, but have > not been able to repro either on an i386 machine or on a KVM guest. > > I run your program ./tty-bug in a tight loop. I will try to run the > program overnight in a loop. > > Given that your program does not depend on NET_NS, can you see if you > can repro on 2.6.28 and see if we can bisect this problem ? Immediate crash. I tried 2.6.18-something (Debian etch kernel) that I had lying around on the VM. The result: idr_remove called for id=0 which is not allocated. [] idr_remove+0xd4/0x137 [] release_mem+0x1d5/0x1e1 [] release_dev+0x5d6/0x5ee [] __wake_up+0x2a/0x3d [] tty_ldisc_enable+0x1f/0x21 [] init_dev+0x378/0x49f [] tty_open+0x2a9/0x2e8 [] chrdev_open+0x126/0x141 [] chrdev_open+0x0/0x141 [] __dentry_open+0xc8/0x1ac [] nameidata_to_filp+0x19/0x28 [] do_filp_open+0x2b/0x31 [] do_nanosleep+0x43/0x6a [] do_sigaction+0x99/0x156 [] do_sys_open+0x3e/0xb3 [] sys_open+0x16/0x18 [] syscall_call+0x7/0xb (on the bright side, the machine is still usable afterwards). However, 2.6.26 (both mine and Debian) survives the test so it may indeed be a recent regression (was it broken again after fixing sometime between .18 and .26?) Bisecting... Best regards, Grzegorz Nosek