From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751986Ab0CTRRU (ORCPT ); Sat, 20 Mar 2010 13:17:20 -0400 Received: from e23smtp08.au.ibm.com ([202.81.31.141]:37027 "EHLO e23smtp08.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751576Ab0CTRRS (ORCPT ); Sat, 20 Mar 2010 13:17:18 -0400 Message-ID: <4BA50319.3040301@in.ibm.com> Date: Sat, 20 Mar 2010 22:47:13 +0530 From: Sachin Sant User-Agent: Thunderbird 2.0.0.22 (X11/20090609) MIME-Version: 1.0 To: linux-kernel CC: Peter Zijlstra , Ingo Molnar Subject: 2.6.34-rc2: cpu hotplug test failure on x86_64 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Running cpu hotplug tests on a x86_64 box results in the following BUG. BUG: unable to handle kernel NULL pointer dereference at 0000000000000004 IP: [] amd_pmu_cpu_offline+0x38/0x67 PGD 0 Oops: 0000 [#1] SMP last sysfs file: /sys/devices/system/cpu/cpu1/online CPU 0 Modules linked in: ipv6 fuse loop dm_mod sg bnx2 rtc_cmos mptctl rtc_core i2c_piix4 rtc_lib serio_raw pcspkr shpchp button i2c_core k8temp pci_hotplug ohci_hcd ehci_hcd sd_mod crc_t10dif usbcore edd ext3 jbd fan thermal processor thermal_sys hwmon mptsas mptscsih mptbase scsi_transport_sas scsi_mod Pid: 7657, comm: bash Not tainted 2.6.34-rc2-autotest #1 Server Blade/BladeCenter LS21 -[79716AA]- RIP: 0010:[] [] amd_pmu_cpu_offline+0x38/0x67 RSP: 0018:ffff880129e11d88 EFLAGS: 00010246 RAX: 0000000000000001 RBX: ffff88000608b6f0 RCX: ffffffff8178f3f0 RDX: 0000000000000000 RSI: 0000000000000007 RDI: ffffffff81930f94 RBP: ffff880129e11d98 R08: 0000000000000000 R09: ffff880129e11ca8 R10: 0000000000000000 R11: 0000000000018600 R12: 00000000fffffffd R13: ffffffff8179f4e0 R14: 0000000000000001 R15: 0000000000000007 FS: 00007f7e4c9346f0(0000) GS:ffff880006000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b CR2: 0000000000000004 CR3: 0000000129f51000 CR4: 00000000000006f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400 Process bash (pid: 7657, threadinfo ffff880129e10000, task ffff88012850b1e0) Stack: ffff880129e11d98 0000000000000000 ffff880129e11da8 ffffffff81388ab3 <0> ffff880129e11de8 ffffffff8139474e 0000000000000001 ffffffff8184c5e0 <0> 0000000000000001 0000000000000000 0000000000000000 0000000000000001 Call Trace: [] x86_pmu_notifier+0x51/0x58 [] notifier_call_chain+0x33/0x5b [] raw_notifier_call_chain+0xf/0x11 [] _cpu_down+0x1ed/0x2f3 [] ? __create_workqueue_key+0x204/0x22c [] cpu_down+0x39/0x53 [] store_online+0x2c/0x6f [] sysdev_store+0x1b/0x1d [] sysfs_write_file+0xdf/0x114 [] vfs_write+0xae/0x16a [] sys_write+0x47/0x6e [] system_call_fastpath+0x16/0x1b Code: b6 80 00 01 76 4f 48 63 c7 48 c7 c3 f0 b6 00 00 48 c7 c7 94 0f 93 81 48 03 1c c5 c0 2e 84 81 e8 00 a2 35 00 48 8b 93 28 07 00 00 <8b> 42 04 ff c8 85 c0 89 42 04 75 0c 48 8b bb 28 07 00 00 e8 ae RIP [] amd_pmu_cpu_offline+0x38/0x67 RSP CR2: 0000000000000004 ---[ end trace d44efb4255454e5f ]--- The problem seem to have been introduced in 2.6.34-rc1-git8(397104793...) I haven't tried a git bisect yet. The following two commits modified the code in perf_event_amd.c. 34538ee77b39a12702e0f4c3ed9e8fa2dd5eb92c 3f6da3905398826d85731247e7fbcf53400c18bd Will try reverting them to check if that helps. Thanks -Sachin -- --------------------------------- Sachin Sant IBM Linux Technology Center India Systems and Technology Labs Bangalore, India ---------------------------------