From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751815AbZHTHyz (ORCPT ); Thu, 20 Aug 2009 03:54:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750806AbZHTHyy (ORCPT ); Thu, 20 Aug 2009 03:54:54 -0400 Received: from mail-ew0-f207.google.com ([209.85.219.207]:41488 "EHLO mail-ew0-f207.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750747AbZHTHyx convert rfc822-to-8bit (ORCPT ); Thu, 20 Aug 2009 03:54:53 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=UpUZ01uG42d0w9CBNckrCNIrGLFngDnFd1X4f63ny3fSPVetcCu8teEFXC6+wGZJSO oESKS+eb/4bzLbKrNdUT7ZBWJRAG4C0KDQaZRqYUrosQMUPIWOge536JqXGd4CYYWkjP QadDv/Wh5Cm2JZNAG0sLQoQd9CarfP9QK6fc4= MIME-Version: 1.0 In-Reply-To: References: Date: Thu, 20 Aug 2009 15:54:53 +0800 Message-ID: Subject: Re: v2.6.31-rc6: BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 From: Dave Young To: "Eric W. Biederman" Cc: linux-kernel@vger.kernel.org, x86@kernel.org, Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Linus Torvalds , Alan Cox , Greg Kroah-Hartman Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Aug 20, 2009 at 2:07 PM, Eric W. Biederman wrote: > > ebiederm@xmission.com (Eric W. Biederman) writes: > >> I'm not certain who I should route this too, but I just had 2.6.31-rc6 >> fall over on me.  I don't know how reproducible this will be but >> I have a full crash dump if someone is interested in looking into this. > > Looks like I was wrong.  This is appears trivial to reproduce, > I have just reproduced it two more times in a row.  I think > the problem is pty related. > > I was looking into a change in behavior on 2.6.31-rc6 where > data was being lost, and it appears one variant of my test program > kills the kernel. > > The following program run as an unprivileged user causes a kernel > panic in about a minute: > > aka > > while :; do ./KernelTtyTest ; done The test app failed for me: read failed: Input/output error lastbytes: '\r\nprocess_cmd read failed: Interrupted system call\r\necho _2_\r\n' Aborted > > > I'm not certain where to start digging into this beyond that. > > Eric > > > > > > >> >> Eric >> >> BUG: unable to handle kernel NULL pointer dereference at 0000000000000008 >> IP: [] run_timer_softirq+0x13a/0x1fa >> PGD 0 >> Thread overran stack, or stack corrupted >> Oops: 0002 [#1] SMP >> last sysfs file: /sys/devices/system/cpu/cpu0/cpufreq/cpuinfo_max_freq >> CPU 0 >> Modules linked in: veth macvlan nfsd lockd nfs_acl auth_rpcgss exportfs sco bridge stp bnep l2cap bluetooth sunrpc ipv6 cpufreq_ondemand acpi_cpufreq freq_table ext4 jbd2 crc16 dm_mirror dm_region_hash dm_log dm_multipath dm_mod uinput kvm_intel kvm fuse xt_multiport iptable_nat ip_tables nf_nat x_tables nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 tun 8021q ixgbe iTCO_wdt iTCO_vendor_support i2c_i801 mdio e1000e pcspkr serio_raw sg ata_generic pata_acpi ata_piix libata sd_mod scsi_mod ext3 jbd mbcache uhci_hcd ohci_hcd ehci_hcd i915 drm i2c_algo_bit i2c_core video output [last unloaded: microcode] >> Pid: 0, comm: swapper Not tainted 2.6.31-rc6-172084.2009.AroraKernelBeta.fc11.x86_64 #1 PDSBM >> RIP: 0010:[]  [] run_timer_softirq+0x13a/0x1fa >> RSP: 0018:ffff8800017cfe30  EFLAGS: 00010006 >> RAX: ffff8800365b2928 RBX: ffffffff81744e40 RCX: 0000000000000000 >> RDX: ffff8800017cfe50 RSI: 0000000000000246 RDI: 0000000000000000 >> RBP: ffff8800017cfea0 R08: ffff8800017d8c00 R09: ffff8800017cff08 >> R10: 6b40fbe55cdd76b4 R11: ffffffff81744e40 R12: ffff8800017cfe50 >> R13: 0000000000000000 R14: ffffffff81746658 R15: ffffffff81746258 >> FS:  0000000000000000(0000) GS:ffff8800017cc000(0000) knlGS:0000000000000000 >> CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b >> CR2: 0000000000000008 CR3: 0000000001001000 CR4: 00000000000026f0 >> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 >> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 >> Process swapper (pid: 0, threadinfo ffffffff815b2000, task ffffffff8153f020) >> Stack: >>  6b40fbe55cdd76b4 ffff880000000100 ffffffff81746a58 ffffffff81745e58 >> <0> ffff8800365b2928 ffff8800abcd6128 ffffffff81023733 6b40fbe55cdd76b4 >> <0> 6b40fbe55cdd76b4 0000000000000008 0000000000000001 0000000000000100 >> Call Trace: >>   >>  [] ? lapic_next_event+0x23/0x3b >>  [] __do_softirq+0xe7/0x1cd >>  [] call_softirq+0x1c/0x28 >>  [] do_softirq+0x51/0xae >>  [] irq_exit+0x52/0xa3 >>  [] smp_apic_timer_interrupt+0x94/0xb9 >>  [] apic_timer_interrupt+0x13/0x20 >>   >>  [] ? mwait_idle+0x9b/0xcc >>  [] ? mwait_idle+0x3d/0xcc >>  [] ? enter_idle+0x33/0x49 >>  [] ? cpu_idle+0xb0/0xf3 >>  [] ? rest_init+0x79/0x8f >>  [] ? start_kernel+0x3dc/0x3fd >>  [] ? x86_64_start_reservations+0xbb/0xd6 >>  [] ? x86_64_start_kernel+0x105/0x128 >> Code: 49 8b 54 1d 20 48 89 55 b8 4c 89 22 49 89 44 1d 20 49 89 44 1d 18 eb 7e 4c 8b 68 18 48 8b 78 20 48 89 43 08 48 8b 08 48 8b 50 08 <48> 89 51 08 48 89 0a 48 c7 40 08 00 02 20 00 48 c7 00 00 00 00 >> RIP  [] run_timer_softirq+0x13a/0x1fa >>  RSP >> CR2: 0000000000000008 > > -- Regards dave