commit 97a9a7179aad701ab676e6f29eb90766a1acfde2 (powerpc/pseries: dynamically added OF nodes need to call of_node_init) will be in 3.16-rc7
** Changed in: linux (Ubuntu Trusty) Status: In Progress => Invalid ** Changed in: linux (Ubuntu Utopic) Status: Fix Released => In Progress ** Changed in: linux (Ubuntu Utopic) Assignee: Canonical Kernel Team (canonical-kernel-team) => Tim Gardner (timg-tpi) -- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1340789 Title: Kernel BUG @of/base.c:251 during attach-device operation on Ubuntu 14.10 LE guest Status in “linux” package in Ubuntu: In Progress Status in “linux” source package in Trusty: Invalid Status in “linux” source package in Utopic: In Progress Bug description: -- Problem Description -- Trying to dynamically add a network device of type virtio to a Ubuntu 14.10 guest running on PowerKVM generates a kernel BUG message. Virsh reports the operation as successful. Steps to recreate the problem : 1) Install 14.10 as a Power KVM guest. 2) Install ppc64-diag package librtas1 1.3.10-1 ppc64el userspace RTAS library librtasevent1 1.3.10-1 ppc64el RTAS events library ppc64-diag 2.6.6-0ubuntu1 ppc64el Platform error log analysis tool and rtas_errd daemon libservicelog-1.1-1:ppc64el 1.1.14-0ubuntu1 ppc64el Library to create and maintain a database for storing events servicelog 1.1.12-0ubuntu1 ppc64el Platform Service/Error Message Database 3) Using a network device definition as mentioned below try a virsh attach-device operation On the PowerKVM host : # cat net <interface type='bridge'> <mac address='52:54:00:A0:9D:9a'/> <source bridge='virbr0'/> <model type='virtio'/> </interface> # virsh attach-device ss_1410_1 net Device attached successfully # Following kernel BUG is observed on the guest [ 6380.112079] RTAS: event: 1, Type: Unknown, Severity: 1 [ 6380.209844] ------------[ cut here ]------------ [ 6380.209848] kernel BUG at /build/buildd/linux-3.15.0/drivers/of/base.c:251! [ 6380.209922] Oops: Exception in kernel mode, sig: 5 [#1] [ 6380.209963] SMP NR_CPUS=2048 NUMA pSeries [ 6380.210006] Modules linked in: pseries_rng rtc_generic e1000 [ 6380.210084] CPU: 0 PID: 3642 Comm: drmgr Not tainted 3.15.0-6-generic #11-Ubuntu [ 6380.210146] task: c0000000770968a0 ti: c000000079858000 task.ti: c000000079858000 [ 6380.210207] NIP: c000000000871c24 LR: c000000000872704 CTR: c000000000080ed0 [ 6380.210268] REGS: c00000007985b7f0 TRAP: 0700 Not tainted (3.15.0-6-generic) [ 6380.210328] MSR: 8000000000029033 <SF,EE,ME,IR,DR,RI,LE> CR: 24002488 XER: 20000000 [ 6380.210473] CFAR: c000000000872700 SOFTE: 1 [ 6380.210473] GPR00: c000000000872704 c00000007985ba70 c000000001791188 c000000004192100 [ 6380.210473] GPR04: 0000000000000001 c00000007e039fc0 c00000000419ee80 c000000001aa1188 [ 6380.210473] GPR08: 0000000000000002 0000000000000001 0000000000000000 c00000000453025b [ 6380.210473] GPR12: 0000000024002482 c00000000fe40000 0000000000000000 000000000000000c [ 6380.210473] GPR16: 000001001e42eeda 0000000000000020 0000000000000000 0000000010016a00 [ 6380.210473] GPR20: 0000000010016950 00000000100167b0 0000000000000001 c00000007e039800 [ 6380.210473] GPR24: c000000000cc0310 c000000004530009 c000000077594f80 c00000007fff6d38 [ 6380.210473] GPR28: 0000000000000015 c000000004192100 c000000001aa01b0 c000000004192100 [ 6380.211355] NIP [c000000000871c24] .of_node_add+0x34/0x110 [ 6380.211397] LR [c000000000872704] .of_attach_node+0xd4/0xf0 [ 6380.211440] Call Trace: [ 6380.211462] [c00000007985ba70] [0000000010016950] 0x10016950 (unreliable) [ 6380.211525] [c00000007985baf0] [c000000000872704] .of_attach_node+0xd4/0xf0 [ 6380.211633] [c00000007985bb70] [c000000000076420] .ofdt_write+0x590/0x780 [ 6380.211753] [c00000007985bc50] [c00000000030727c] .proc_reg_write+0xac/0x110 [ 6380.211815] [c00000007985bcf0] [c000000000279370] .vfs_write+0xe0/0x260 [ 6380.211876] [c00000007985bd90] [c00000000027a034] .SyS_write+0x64/0x110 [ 6380.211939] [c00000007985be30] [c000000000009ffc] syscall_exit+0x0/0x7c [ 6380.212001] Instruction dump: [ 6380.212033] fbc1fff0 fbe1fff8 f8010010 f821ff81 7c7f1b78 60000000 60000000 2fbf0000 [ 6380.212142] 419e006c 813f0094 69290001 792907e0 <0b090000> 3fc2ffeb 3bdefe60 7fc3f378 [ 6380.212250] ---[ end trace 410b60b95ac50ef5 ]--- [ 6380.214151] sachin@1410:/var/log$ sachin@1410:/var/log$ cat /etc/issue Ubuntu Utopic Unicorn (development branch) \n \l sachin@1410:/var/log$ uname -a Linux 1410 3.15.0-6-generic #11-Ubuntu SMP Thu Jun 12 00:40:49 UTC 2014 ppc64le ppc64le ppc64le GNU/Linux sachin@1410:/var/log$ The BUG_ON() it is hitting is likely this one: int of_node_add(struct device_node *np) { int rc = 0; BUG_ON(!of_node_is_initialized(np)); This appears to be related to commit 75b57ecf9d1d1e17d099ab13b8f48e6e038676be. This was part of the updates that Grant did to move the device tree from /proc/to sysfs. As part of this he removed the kref_init call we made prior to adding the device node. Attached patch "powerpc/pseries: dynamically added OF nodes need to call of_node_init" With the attach patch, the attach/detach device operation works correctly. No kernel BUG is observed. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1340789/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp