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---Problem Description---
Ubuntu 16.10: System hangs after crash on Ubuntu KVM guest.
---Steps to Reproduce---
1) apt-get install linux-crashdump
2) increase crashdump size:
sudo vim /etc/default/grub.d/kexec-tools.cfg
GRUB_CMDLINE_LINUX_DEFAULT="$GRUB_CMDLINE_LINUX_DEFAULT crashkernel=2G-
4G:320M,4G-32G:512M,32G-64G:1024M,64G-128G:2048M,128G-:4096M"
3) sudo update-grub ; reboot the machine
4) sudo sed -i 's/USE_KDUMP=0/USE_KDUMP=1/g' /etc/default/kdump-tools
5) kdump-config show
6) echo "c" > /proc/sysrq-trigger
Logs
====
root@ubuntu:/var/crash# uname -a
Linux ubuntu 4.8.0-17-generic #19-Ubuntu SMP Sun Sep 25 06:35:40 UTC 2016
ppc64le ppc64le ppc64le GNU/Linux
root@ubuntu:/var/crash# kdump-config show
DUMP_MODE: kdump
USE_KDUMP: 1
KDUMP_SYSCTL: kernel.panic_on_oops=1
KDUMP_COREDIR: /var/crash
crashkernel addr:
/var/lib/kdump/vmlinuz: symbolic link to /boot/vmlinux-4.8.0-17-generic
kdump initrd:
/var/lib/kdump/initrd.img: symbolic link to
/var/lib/kdump/initrd.img-4.8.0-17-generic
current state: ready to kdump
kexec command:
/sbin/kexec -p --command-line="BOOT_IMAGE=/boot/vmlinux-4.8.0-17-generic
root=UUID=70f3c690-fe90-444d-a74c-71c05eef8b0e ro splash quiet irqpoll
nr_cpus=1 nousb systemd.unit=kdump-tools.service"
--initrd=/var/lib/kdump/initrd.img /var/lib/kdump/vmlinuz
root@ubuntu:/var/crash# echo c > /proc/sysrq-trigger
[ 202.677946] sysrq: SysRq : Trigger a crash
[ 202.678018] Unable to handle kernel paging request for data at address
0x00000000
[ 202.678098] Faulting instruction address: 0xc0000000006de134
[ 202.678169] Oops: Kernel access of bad area, sig: 11 [#1]
[ 202.678222] SMP NR_CPUS=2048 NUMA pSeries
[ 202.678281] Modules linked in: vmx_crypto ip_tables x_tables autofs4
ibmvscsi crc32c_vpmsum 8139too 8139cp mii
[ 202.678465] CPU: 3 PID: 1992 Comm: bash Not tainted 4.8.0-17-generic
#19-Ubuntu
[ 202.678547] task: c000000004c5ce00 task.stack: c00000000428c000
[ 202.678612] NIP: c0000000006de134 LR: c0000000006df218 CTR: c0000000006de100
[ 202.678716] REGS: c00000000428f990 TRAP: 0300 Not tainted
(4.8.0-17-generic)
[ 202.678796] MSR: 8000000000009033 <SF,EE,ME,IR,DR,RI,LE> CR: 28242222 XER:
20000000
[ 202.678992] CFAR: c000000000014f84 DAR: 0000000000000000 DSISR: 42000000
SOFTE: 1
GPR00: c0000000006df218 c00000000428fc10 c0000000014e5e00 0000000000000063
GPR04: c00000007fecaca0 c00000007fedfb40 c00000000168d278 0000000000004b78
GPR08: 0000000000000007 0000000000000001 0000000000000000 0000000000000001
GPR12: c0000000006de100 c000000007b81b00 ffffffffffffffff 0000000022000000
GPR16: 0000000010170dc8 0000010020c60488 0000000010140f58 00000000100c7570
GPR20: 0000000000000000 000000001017dd58 0000000010153618 000000001017b608
GPR24: 00003fffd5f377c4 0000000000000001 c0000000013fe5d0 0000000000000004
GPR28: c0000000013fe990 0000000000000063 c0000000013b2590 0000000000000000
[ 202.680090] NIP [c0000000006de134] sysrq_handle_crash+0x34/0x50
[ 202.680159] LR [c0000000006df218] __handle_sysrq+0xe8/0x280
[ 202.680213] Call Trace:
[ 202.680246] [c00000000428fc10] [c000000000e79720]
_fw_tigon_tg3_bin_name+0x2f1a8/0x36f48 (unreliable)
[ 202.680356] [c00000000428fc30] [c0000000006df218] __handle_sysrq+0xe8/0x280
[ 202.680440] [c00000000428fcd0] [c0000000006df9c8]
write_sysrq_trigger+0x78/0xa0
[ 202.680535] [c00000000428fd00] [c0000000003cf890] proc_reg_write+0xb0/0x110
[ 202.680618] [c00000000428fd50] [c00000000032b5dc] __vfs_write+0x6c/0xe0
[ 202.680702] [c00000000428fd90] [c00000000032cae4] vfs_write+0xd4/0x240
[ 202.680783] [c00000000428fde0] [c00000000032e7fc] SyS_write+0x6c/0x110
[ 202.680867] [c00000000428fe30] [c000000000009584] system_call+0x38/0xec
[ 202.680948] Instruction dump:
[ 202.680991] 38427d00 7c0802a6 f8010010 f821ffe1 60000000 60000000 3d22001a
3949d1e0
[ 202.681133] 39200001 912a0000 7c0004ac 39400000 <992a0000> 38210020 e8010010
7c0803a6
[ 202.681276] ---[ end trace 3e9cbc319000fff4 ]---
[ 202.684658]
[ 202.684718] Sending IPI to other CPUs
[ 202.686765] IPI complete
I'm in purgatory
-> smp_release_cpus()
spinning_secondaries = 3
<- smp_release_cpus()
Linux ppc64le
#19-Ubuntu SMP S[ 242.661649] INFO: task swapper/0:1 blocked for more than 120
seconds.
[ 242.661708] Not tainted 4.8.0-17-generic #19-Ubuntu
[ 242.661746] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
message.
[ 363.493648] INFO: task swapper/0:1 blocked for more than 120 seconds.
[ 363.493712] Not tainted 4.8.0-17-generic #19-Ubuntu
[ 363.493755] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
message.
[ 484.325651] INFO: task swapper/0:1 blocked for more than 120 seconds.
[ 484.325704] Not tainted 4.8.0-17-generic #19-Ubuntu
[ 484.325738] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
message.
[ 605.157653] INFO: task swapper/0:1 blocked for more than 120 seconds.
[ 605.157712] Not tainted 4.8.0-17-generic #19-Ubuntu
[ 605.157750] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
message.
[ 725.989649] INFO: task swapper/0:1 blocked for more than 120 seconds.
Observing hang in scheduler while booting kdump kernel with "nr_cpus=1"
on KVM guest.
[c00000001a06aeb0] [c00000000801ac1c] __switch_to+0x29c/0x420
[c00000001a06af10] [c000000008b8c414] __schedule+0x2f4/0x9b0
[c00000001a06aff0] [c000000008b8cb18] schedule+0x48/0xc0
Need to debug further to find the root cause.
The issue is not seen with "maxcpus=1" parameter. As a workaround,
please use "maxcpus=1" instead of "nr_cpus=1" for other kdump tests..
Thanks
Hari
** Affects: linux (Ubuntu)
Importance: Undecided
Assignee: Taco Screen team (taco-screen-team)
Status: New
** Tags: architecture-ppc64le bugnameltc-147161 severity-high
targetmilestone-inin1610
--
Ubuntu 16.10: System hangs after crash on Ubuntu KVM guest.
https://bugs.launchpad.net/bugs/1635063
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