From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeremy Fitzhardinge Subject: Re: Null-pointer access in netback_uevent Date: Thu, 27 May 2010 14:03:15 -0700 Message-ID: <4BFEDE13.5020507@goop.org> References: <20100527165558.GA11358@wavehammer.waldi.eu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20100527165558.GA11358@wavehammer.waldi.eu.org> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Bastian Blank , xen-devel@lists.xensource.com List-Id: xen-devel@lists.xenproject.org On 05/27/2010 09:55 AM, Bastian Blank wrote: > My slightly patched kernel based on > f6fe6583b77a49b569eef1b66c3d761eec2e561b failed with null-pointer access in > netback_uevent. > What were you doing at the time? J > | BUG: unable to handle kernel NULL pointer dereference at 0000000000000150 > | IP: [] netback_uevent+0x83/0xaf > > According to gdb the following is the culprit: > > | 185 if (add_uevent_var(env, "vif=%s", netif->dev->name)) > | 0x0000000000002313 <+131>: mov 0x150(%r13),%rdx > > Complete oops: > > | BUG: unable to handle kernel NULL pointer dereference at 0000000000000150 > | IP: [] netback_uevent+0x83/0xaf > | PGD ce0b1067 PUD ce193067 PMD 0 > | Oops: 0000 [#1] SMP > | last sysfs file: /sys/devices/vif-1-0/uevent > | CPU 1 > | Modules linked in: blktap xen_evtchn xenfs xt_tcpudp xt_state iptable_filter ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_conntrack nf_defrag_ipv4 ip_tables x_tables bridge stp dm_snapshot loop snd_pcm snd_timer snd soundcore tpm_tis radeon snd_page_alloc ttm drm_kms_helper psmouse tpm drm pcspkr amd64_edac_mod ipmi_si tpm_bios evdev serio_raw edac_core i2c_algo_bit shpchp ipmi_msghandler i2c_piix4 edac_mce_amd container i2c_core hpilo processor pci_hotplug button acpi_processor hpwdt ext3 jbd mbcache dm_mod cciss ata_generic libata scsi_mod bnx2 thermal thermal_sys [last unloaded: xen_evtchn] > | Pid: 8076, comm: udevd Tainted: G W 2.6.32-5-xen-amd64 #2 ProLiant DL385 G6 > | RIP: e030:[] [] netback_uevent+0x83/0xaf > | RSP: e02b:ffff880002af7e18 EFLAGS: 00010246 > | RAX: 01000000000000c1 RBX: ffff8800029f6000 RCX: 0000000000800078 > | RDX: ffff8800c33b13a0 RSI: ffffea0002ab4eb8 RDI: 01000000000002c0 > | RBP: ffff8800c33b14e0 R08: 0000000000000000 R09: ffffffff814664f0 > | R10: 0000000000000200 R11: ffffffff8100f19c R12: ffff880002f39c00 > | R13: 0000000000000000 R14: ffff8800021db000 R15: ffff8800c5026980 > | FS: 00007fbd86ad2790(0000) GS:ffff880003a64000(0000) knlGS:0000000000000000 > | CS: e033 DS: 0000 ES: 0000 CR0: 000000008005003b > | CR2: 0000000000000150 CR3: 00000000025f4000 CR4: 0000000000000660 > | DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 > | DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 > | Process udevd (pid: 8076, threadinfo ffff880002af6000, task ffff88000246c6a0) > | Stack: > | 0000000000000908 ffff880002f39c40 ffff8800029f6000 ffff8800c3795c30 > | ffff8800029f6000 ffffffff8122d9f6 ffff880002f39c50 ffff8800c3795c30 > | ffffffff814a80d0 0000000000000000 ffff880002f39c50 ffffffff8122db35 > | Call Trace: > | [] ? dev_uevent+0x104/0x146 > | [] ? show_uevent+0x81/0xd5 > | [] ? dev_attr_show+0x1f/0x42 > | [] ? sysfs_read_file+0xa7/0x125 > | [] ? vfs_read+0xa6/0xff > | [] ? sys_read+0x45/0x6e > | [] ? system_call_fastpath+0x16/0x1b > | Code: c7 c6 fe 1c 3f 81 31 c0 48 89 df e8 44 fe f8 ff 85 c0 74 0f 48 89 ef bb f4 ff ff ff e8 39 70 ee ff eb 2a 48 89 ef e8 2f 70 ee ff <49> 8b 95 50 01 00 00 48 89 df 31 c0 48 c7 c6 08 1d 3f 81 e8 11 > | RIP [] netback_uevent+0x83/0xaf > | RSP > | CR2: 0000000000000150 > | ---[ end trace a7919e7f17c0a727 ]--- > > Bastian > >