From mboxrd@z Thu Jan 1 00:00:00 1970 From: Frank van Maarseveen Subject: Re: BUG: unable to handle kernel paging request at virtual address 6b6b6b6f Date: Tue, 3 Jul 2007 22:22:16 +0200 Message-ID: <20070703202216.GB16497@janus> References: <20070703071735.GA9481@janus> <20070703193937.GM14074@fieldses.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Cc: Linux NFS mailing list To: "J. Bruce Fields" Return-path: Received: from sc8-sf-mx2-b.sourceforge.net ([10.3.1.92] helo=mail.sourceforge.net) by sc8-sf-list2-new.sourceforge.net with esmtp (Exim 4.43) id 1I5ot7-0007we-95 for nfs@lists.sourceforge.net; Tue, 03 Jul 2007 13:22:17 -0700 Received: from frankvm.xs4all.nl ([80.126.170.174] helo=janus.localdomain) by mail.sourceforge.net with esmtp (Exim 4.44) id 1I5ot8-0001Bq-Kf for nfs@lists.sourceforge.net; Tue, 03 Jul 2007 13:22:20 -0700 In-Reply-To: <20070703193937.GM14074@fieldses.org> List-Id: "Discussion of NFS under Linux development, interoperability, and testing." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: nfs-bounces@lists.sourceforge.net Errors-To: nfs-bounces@lists.sourceforge.net On Tue, Jul 03, 2007 at 03:39:37PM -0400, J. Bruce Fields wrote: > On Tue, Jul 03, 2007 at 09:17:35AM +0200, Frank van Maarseveen wrote: > > I've reported this earlier but now I figured out how to reproduce it: > > start nfsd with 50 instances and then try to stop it. > > So, all it takes is this?: > > rpc.nfsd 50 > rpc.nfsd 0 I guess so: On debian etch I adapted /etc/defaults/nfs-kernel-server (IIRC) to start 50 daemons and after a reboot it sufficed to type /etc/init.d/nfs-kernel-server stop to make it say BUG. Very reproducable here (5 machines). > > > > > Jul 3 09:10:39 kernel: BUG: unable to handle kernel paging request at virtual address 6b6b6b6f > > Jul 3 09:10:39 kernel: printing eip: > > Jul 3 09:10:39 kernel: c053f594 > > Jul 3 09:10:39 kernel: *pde = 00000000 > > Jul 3 09:10:39 kernel: Oops: 0000 [#1] > > Jul 3 09:10:39 kernel: SMP > > Jul 3 09:10:39 kernel: Modules linked in: vmthrottle > > What's vmthrottle, by the way? That's a custom module to kill memory hungry processes when the uid doesn't match the one running the X server (basically). That way 40-50 workstations for software development can also participate in distributed compiler testing without interfering too much. An unpatched and moduleless kernel still crashes. > > > Jul 3 09:10:39 kernel: CPU: 1 > > Jul 3 09:10:39 kernel: EIP: 0060:[] Not tainted VLI > > Jul 3 09:10:39 kernel: EFLAGS: 00010202 (2.6.21.5-x160 #1) > > Jul 3 09:10:39 kernel: EIP is at cache_clean+0x124/0x1e0 > > Jul 3 09:10:39 kernel: eax: 00000000 ebx: 6b6b6b6b ecx: c06dffa0 edx: c0a1f380 > > Jul 3 09:10:39 kernel: esi: f672d800 edi: 00000000 ebp: f5a11f40 esp: f5a11f34 > > Jul 3 09:10:39 kernel: ds: 007b es: 007b fs: 00d8 gs: 0000 ss: 0068 > > Jul 3 09:10:39 kernel: Process nfsd (pid: 4420, ti=f5a10000 task=f596c070 task.ti=f5a10000) > > Jul 3 09:10:39 kernel: Stack: c06dffa0 f6a3c268 f6a3c234 f5a11f48 c053f69f f5a11f54 c053f6da f6a3c260 > > Jul 3 09:10:39 kernel: f5a11f5c c020ef47 f5a11f70 c0205632 c06597c8 f6a3c268 f6a3c7ac f5a11f94 > > Jul 3 09:10:39 kernel: c0537b23 f59b2000 f5a11f94 00000286 f6a3c270 f59b2000 f6a3c7ac f6a3c234 > > Jul 3 09:10:39 kernel: Call Trace: > > Jul 3 09:10:39 kernel: [] show_trace_log_lvl+0x19/0x30 > > Jul 3 09:10:39 kernel: [] show_stack_log_lvl+0x8b/0xb0 > > Jul 3 09:10:39 kernel: [] show_registers+0x1e6/0x310 > > Jul 3 09:10:39 kernel: [] die+0x10f/0x240 > > Jul 3 09:10:39 kernel: [] do_page_fault+0x342/0x610 > > Jul 3 09:10:39 kernel: [] error_code+0x7c/0x90 > > Jul 3 09:10:39 kernel: [] cache_flush+0xf/0x30 > > Jul 3 09:10:39 kernel: [] cache_purge+0x1a/0x30 > > Jul 3 09:10:39 kernel: [] nfsd_export_flush+0x17/0x30 > > So I guess the nfsd export cache is corrupted somehow. > > Perhaps turning on more debugging options in the kernel config would > help catch the problem earlier. I'm not having any luck reproducing > this now. Hmm, 6b6b6b6b looks like a poison to me and I have some debugging options on: CONFIG_DEBUG_KERNEL=y CONFIG_SLAB=y CONFIG_DEBUG_SLAB=y CONFIG_DETECT_SOFTLOCKUP=y CONFIG_DEBUG_SPINLOCK=y CONFIG_DEBUG_MUTEXES=y CONFIG_DEBUG_LOCK_ALLOC=y CONFIG_DEBUG_SPINLOCK_SLEEP=y CONFIG_DEBUG_BUGVERBOSE=y CONFIG_DEBUG_STACKOVERFLOW=y Full config: http://www.frankvm.com/tmp/dot-config-cachebug -- Frank ------------------------------------------------------------------------- This SF.net email is sponsored by DB2 Express Download DB2 Express C - the FREE version of DB2 express and take control of your XML. No limits. Just data. Click to get it now. http://sourceforge.net/powerbar/db2/ _______________________________________________ NFS maillist - NFS@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/nfs