[Crash-utility] Crash, won't read my vmcore "crash: page excluded: kernel virtual address:"

Tue Feb 11 14:53:20 UTC 2014

----- Original Message -----
> Dave Anderson reached out and wrote:
> 
> ----- Original Message -----
> > [root kvm7 127.0.0.1-2014-02-07-19:17:09]# crash
> > /boot/System.map-2.6.32-220.el6.x86_64.debug
> > /usr/lib/debug/lib/modules/2.6.32-220.el6.x86_64.debug/vmlinux vmcore
> > 
> > crash 5.1.8-1.el6
> > Copyright (C) 2002-2011 Red Hat, Inc.
> > Copyright (C) 2004, 2005, 2006 IBM Corporation
> > Copyright (C) 1999-2006 Hewlett-Packard Co
> > Copyright (C) 2005, 2006 Fujitsu Limited
> > Copyright (C) 2006, 2007 VA Linux Systems Japan K.K.
> > Copyright (C) 2005 NEC Corporation
> > Copyright (C) 1999, 2002, 2007 Silicon Graphics, Inc.
> > Copyright (C) 1999, 2000, 2001, 2002 Mission Critical Linux, Inc.
> > This program is free software, covered by the GNU General Public License,
> > and you are welcome to change it and/or distribute copies of it under
> > certain conditions. Enter "help copying" to see the conditions.
> > This program has absolutely no warranty. Enter "help warranty" for details.
> > GNU gdb (GDB) 7.0
> > Copyright (C) 2009 Free Software Foundation, Inc.
> > License GPLv3+: GNU GPL version 3 or later <
> > http://gnu.org/licenses/gpl.html
> > > 
> > This is free software: you are free to change and redistribute it.
> > There is NO WARRANTY, to the extent permitted by law. Type "show copying"
> > and "show warranty" for details.
> > This GDB was configured as "x86_64-unknown-linux-gnu"...
> > 
> > crash: page excluded: kernel virtual address: ffffffff81542000 type: "cpu_possible_mask"
> > 
> > I can go into minimal,
> > 
> > 
> > nm -Bn /usr/lib/debug/lib/modules/2.6.32-220.el6.x86_64.debug/vmlinux |
> > grep _stext
> > ffffffff81000198 T _stext
> > 
> > cat /proc/kallsyms | grep _stext
> > ffffffff81000198 T _stext
> > 
> > If I use the System Map parm I get this warning
> > 
> > WARNING: kernels compiled by different gcc versions:
> > /usr/lib/debug/lib/modules/2.6.32-220.el6.x86_64.debug/vmlinux: 4.4.5
> > vmcore kernel: 4.4.6
> > 
> > 
> > Would really like to understand why this system crashed. I know I'm a bit
> > behind on my kernel versions however, but I should be able to look at this
> > kernel??
> > 
> > Thanks
> > Tory
> 
> It looks like the vmcore and vmlinux file don't match, like maybe the crashing
> system was running the standard 2.6.32-220.el6.x86_64 kernel, and you're trying
> to debug it using the 2.6.32-220.el6.x86_64.debug kernel variant?
> 
> First thing -- *never* use a System.map file unless for some reason you don't
> have the original kernel's vmlinux available *and* you feel that the vmlinux
> file you have is very close to the crashing kernel's vmlinux. Bit with any
> RHEL standard (unmodified) vmlinux/vmcore setup, the System.map is completely
> useless.
> 
> So the first question is: what kernel generated the vmcore?
> 
> Do this:
> 
> $ strings vmcore | grep '2.6.32'
> Dave
> 
> 
> --
> Dave you are right, I thought I had to use the devel kernel and in fact my
> system is not running that, so it crashed with the standard 2.6.32-220.el6.x86_64 kernel.
> 
> [tblue at kvm7 127.0.0.1-2014-02-07-19:17:09]$ sudo strings vmcore | grep '2.6.32'
> 
> 2.6.32-220.el6.x86_64
> OSRELEASE=2.6.32-220.el6.x86_64
> 
> But it won't take my vmlinux from /boot
> 
> crash: /boot/vmlinuz-2.6.32-220.el6.x86_64: not a supported file format

There is no vmlinux file in /boot.  The "vmlinuz" (with-a-z) file is not usable.
You will always need the vmlinux from from the associated kernel-debuginfo rpm.

> Yes sir you were correct, I was using the wrong kernel!
> 
> please wait... (determining panic task)
> WARNING: multiple active tasks have called die
> 
> KERNEL: /usr/lib/debug/lib/modules/2.6.32-220.el6.x86_64/vmlinux
> DUMPFILE: /libvirt/crash/127.0.0.1-2014-02-07-19:17:09/vmcore [PARTIAL DUMP]
> CPUS: 32
> DATE: Fri Feb 7 18:16:05 2014
> UPTIME: 226 days, 21:36:13
> LOAD AVERAGE: 2.42, 2.68, 2.69
> TASKS: 816
> NODENAME: kvm7.domain.com
> RELEASE: 2.6.32-220.el6.x86_64
> VERSION: #1 SMP Tue Dec 6 19:48:22 GMT 2011
> MACHINE: x86_64 (2200 Mhz)
> MEMORY: 88 GB
> PANIC: ""
> PID: 0
> COMMAND: "swapper"
> TASK: ffff881665514b40 (1 of 32) [THREAD_INFO: ffff880c6124e000]
> CPU: 19
> STATE: TASK_RUNNING (PANIC)
> 
> Nothing stands out as s bug or reason to fail
> 
> divide error: 0000 [#1] SMP
> last sysfs file: /sys/devices/system/cpu/cpu31/cache/index2/shared_cpu_map
> CPU 19
> Modules linked in: ext3 jbd ip6table_filter ip6_tables ebtable_nat ebtables
> ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_state
> nf_conntrack ipt_REJECT xt_CHECKSUM iptable_mangle iptable_filter ip_tables
> sunrpc bridge stp llc bonding ipv6 vhost_net macvtap macvlan tun kvm_intel
> kvm cdc_ether usbnet mii microcode i2c_i801 i2c_core iTCO_wdt
> iTCO_vendor_support shpchp igb ioatdma dca ses enclosure sg ext4 mbcache
> jbd2 sr_mod cdrom sd_mod crc_t10dif ahci megaraid_sas dm_mirror
> dm_region_hash dm_log dm_mod [last unloaded: scsi_wait_scan]
> 
> Pid: 0, comm: swapper Not tainted 2.6.32-220.el6.x86_64 #1 IBM System x3650
> M4 -[7915AC1]-/00J6528
> RIP: 0010:[<ffffffff81054ad5>] [<ffffffff81054ad5>] find_busiest_group+0x5c5/0xb20
> RSP: 0018:ffff880028363c40 EFLAGS: 00010246
> RAX: 0000000000000000 RBX: ffff880028363e64 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: ffff8800282cf540 RDI: ffff8800282d5fc0
> RBP: ffff880028363dd0 R08: ffff8800282cf860 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000001 R12: 00000000ffffff01
> R13: 0000000000015fc0 R14: ffffffffffffffff R15: 0000000000000000
> FS: 0000000000000000(0000) GS:ffff880028360000(0000) knlGS:0000000000000000
> CS: 0010 DS: 0018 ES: 0018 CR0: 000000008005003b
> CR2: 00007f4e5215c000 CR3: 00000011bea54000 CR4: 00000000000426e0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
> Process swapper (pid: 0, threadinfo ffff880c6124e000, task ffff881665514b40)
> Stack:
> ffff880028363d70 ffff880028363ce0 ffff880028363ca0 000000000000024d
> <0> ffff8800282cf860 ffff880028363e58 0101881664b121a8 0000000600000000
> <0> 0000000600000000 ffff8800282cf540 0000000123386cc0 0000000000000008
> Call Trace:
> <IRQ>
> [<ffffffffa02e4669>] ? br_handle_frame_finish+0x179/0x2a0 [bridge]
> [<ffffffff8105fc52>] rebalance_domains+0x1a2/0x5b0
> [<ffffffff81060153>] run_rebalance_domains+0xf3/0x160
> [<ffffffff8107c4f0>] ? get_next_timer_interrupt+0x1b0/0x250
> [<ffffffff81072161>] __do_softirq+0xc1/0x1d0
> [<ffffffff81097e0a>] ? sched_clock_idle_wakeup_event+0x1a/0x20
> [<ffffffff8100c24c>] call_softirq+0x1c/0x30
> [<ffffffff8100de85>] do_softirq+0x65/0xa0
> [<ffffffff81071f45>] irq_exit+0x85/0x90
> [<ffffffff8102a255>] smp_call_function_single_interrupt+0x35/0x40
> [<ffffffff8100bdb3>] call_function_single_interrupt+0x13/0x20
> <EOI>
> [<ffffffff812c4a5e>] ? intel_idle+0xde/0x170
> [<ffffffff812c4a41>] ? intel_idle+0xc1/0x170
> [<ffffffff813f9f47>] cpuidle_idle_call+0xa7/0x140
> [<ffffffff81009e06>] cpu_idle+0xb6/0x110
> [<ffffffff814e5f23>] start_secondary+0x202/0x245
> Code: d0 b8 01 00 00 00 48 c1 ea 0a 48 85 d2 0f 45 c2 41 89 40 08 66 90 4c 8b
> 85 e0 fe ff ff 48 8b 45 a8 31 d2 41 8b 48 08 48 c1 e0 0a <48> f7 f1 48 8b 4d
> b0 48 89 45 a0 31 c0 48 85 c9 74 0c 48 8b 45
> RIP [<ffffffff81054ad5>] find_busiest_group+0x5c5/0xb20
> RSP <ffff880028363c40>
> 
> Is there a forum that would help me figure out what exactly cause this crash
> as it's not the first time, across this series of servers running KVM
> 
> Thank you sir,
> 
> Tory

>From the information above, there was a divide-by-zero fault in find_busiest_group().
If you ran the "bt" command on the panic task, it might be a little more obvious,
but the "divide error: 0000 [#1] SMP" string comes from the divide_error() function.

Anyway, you are running 2.6.32-220.el6, and from a more recent kernel.spec changelog, 
this issue was fixed in 2.6.32-248.el6:

* Tue Mar 06 2012 Aristeu Rozanski <arozansk at redhat.com> [2.6.32-248.el6]
- [netdrv] bnx2: revert firmware load modifications (Neil Horman) [720428]
- [virt] virtio: balloon: leak / fill balloon across S4 (Amit Shah) [798583]
- [scsi] silencing 'killing requests for dead queue' (David Milburn) [798672]
- [scsi] sd_dif: fix setting bio flags (Jeff Moyer) [799075]
- [scsi] megaraid_sas: driver update to version 00.00.06.14-rh1 (Tomas Henzl) [749923]
- [infiniband] srp: fix include ordering issue (Doug Ledford) [791209]
- [sched] Fix Kernel divide by zero panic in find_busiest_group() (Larry Woodman) [785959]   

Time to upgrade...

Dave