Re: [vlan_device_event] BUG: unable to handle kernel paging request at 6b6b6ccf

From: Fengguang Wu
Date: Thu Nov 09 2017 - 02:43:25 EST


On Thu, Nov 09, 2017 at 02:55:10PM +0800, Fengguang Wu wrote:
On Wed, Nov 08, 2017 at 10:34:10PM -0800, Cong Wang wrote:
On Wed, Nov 8, 2017 at 7:12 PM, Fengguang Wu <fengguang.wu@xxxxxxxxx> wrote:
Hi Alex,

So looking over the trace the panic seems to be happening after a
decnet interface is getting deleted. Is there any chance we could try
compiling the kernel without decnet support to see if that is the
source of these issues? I don't know if anyone on the Intel Wired Lan
team is testing with that enabled so if we can eliminate that as a
possible cause that would be useful.


Sure and thank you for the suggestion!

It looks disabling DECNET still triggers the vlan_device_event BUG.
However when looking at the dmesgs, I find another warning just before
the vlan_device_event BUG. Not sure if it's related one or independent
now-fixed issue.

Those decnet symbols are probably noises.

Yes it's not related to CONFIG_DECNET.

How do you reproduce it? And what is your setup? Vlan device on
top of your eth0 (e1000)?

It can basically be reproduced in one of our test machines --
lkp-wsx03, which is a Westmere EX server.

Anyway if you'd like to try, here are the steps. It'll auto download
the images and run QEMU.

apt-get install lib32gcc-7-dev # or lib32gcc-6-dev
git clone https://github.com/intel/lkp-tests.git
cd lkp-tests
bin/lkp qemu -k <bzImage> job-script # job-script is attached in this email

Note that even in our lkp-wsx03 machine, the chance of reproducing it
is only 3% (3 out of 100 boots).

Thanks,
Fengguang
#!/bin/sh

export_top_env()
{
export suite='trinity'
export testcase='trinity'
export runtime=300
export job_origin='/lkp/lkp/src/allot/rand/vm-lkp-wsx03-openwrt-i386/trinity.yaml'
export testbox='vm-lkp-wsx03-openwrt-i386-5'
export tbox_group='vm-lkp-wsx03-openwrt-i386'
export kconfig='i386-randconfig-b0-11061302-CONFIG_DRM_BOCHS'
export compiler='gcc-6'
export queue='wfg'
export branch='linus/master'
export commit='c470abd4fde40ea6a0846a2beab642a578c0b8cd'
export submit_id='5a03a4550b9a93f7c99708b0'
export job_file='/lkp/scheduled/vm-lkp-wsx03-openwrt-i386-5/trinity-300s-openwrt-i386-2016-03-16.cgz-c470abd4fde40ea6a0846a2beab642a578c0b8cd-20171109-63433-kf9gj3-wait_kernel-0.yaml'
export id='181954ca4367d475b88dc8de99b2d52ab533a5e1'
export model='qemu-system-i386 -enable-kvm'
export nr_vm=32
export nr_cpu=1
export memory='320M'
export rootfs='openwrt-i386-2016-03-16.cgz'
export hdd_partitions='/dev/vda'
export swap_partitions='/dev/vdb'
export need_kconfig='CONFIG_KVM_GUEST=y'
export enqueue_time='2017-11-09 08:41:58 +0800'
export _id='5a03a4560b9a93f7c99708bb'
export _rt='/result/trinity/300s/vm-lkp-wsx03-openwrt-i386/openwrt-i386-2016-03-16.cgz/i386-randconfig-b0-11061302-CONFIG_DRM_BOCHS/gcc-6/c470abd4fde40ea6a0846a2beab642a578c0b8cd'
export user='lkp'
export result_root='/result/trinity/300s/vm-lkp-wsx03-openwrt-i386/openwrt-i386-2016-03-16.cgz/i386-randconfig-b0-11061302-CONFIG_DRM_BOCHS/gcc-6/c470abd4fde40ea6a0846a2beab642a578c0b8cd/0'
export LKP_SERVER='inn'
export max_uptime=1500
export initrd='/osimage/openwrt/openwrt-i386-2016-03-16.cgz'
export bootloader_append='root=/dev/ram0
user=lkp
job=/lkp/scheduled/vm-lkp-wsx03-openwrt-i386-5/trinity-300s-openwrt-i386-2016-03-16.cgz-c470abd4fde40ea6a0846a2beab642a578c0b8cd-20171109-63433-kf9gj3-wait_kernel-0.yaml
ARCH=i386
kconfig=i386-randconfig-b0-11061302-CONFIG_DRM_BOCHS
branch=linus/master
commit=c470abd4fde40ea6a0846a2beab642a578c0b8cd
BOOT_IMAGE=/pkg/linux/i386-randconfig-b0-11061302-CONFIG_DRM_BOCHS/gcc-6/c470abd4fde40ea6a0846a2beab642a578c0b8cd/vmlinuz-4.10.0
max_uptime=1500
RESULT_ROOT=/result/trinity/300s/vm-lkp-wsx03-openwrt-i386/openwrt-i386-2016-03-16.cgz/i386-randconfig-b0-11061302-CONFIG_DRM_BOCHS/gcc-6/c470abd4fde40ea6a0846a2beab642a578c0b8cd/0
LKP_SERVER=inn
debug
apic=debug
sysrq_always_enabled
rcupdate.rcu_cpu_stall_timeout=100
net.ifnames=0
printk.devkmsg=on
panic=-1
softlockup_panic=1
nmi_watchdog=panic
oops=panic
load_ramdisk=2
prompt_ramdisk=0
drbd.minor_count=8
systemd.log_level=err
ignore_loglevel
console=tty0
earlyprintk=ttyS0,115200
console=ttyS0,115200
vga=normal
rw'
export lkp_initrd='/lkp/lkp/lkp-i386.cgz'
export bm_initrd='/osimage/pkg/static/trinity-i386.cgz'
export site='inn'
export LKP_CGI_PORT=80
export LKP_CIFS_PORT=139
export vmlinux_file='/pkg/linux/i386-randconfig-b0-11061302-CONFIG_DRM_BOCHS/gcc-6/c470abd4fde40ea6a0846a2beab642a578c0b8cd/vmlinux'
export kernel='/pkg/linux/i386-randconfig-b0-11061302-CONFIG_DRM_BOCHS/gcc-6/c470abd4fde40ea6a0846a2beab642a578c0b8cd/vmlinuz-4.10.0'
export dequeue_time='2017-11-09 09:06:15 +0800'
export job_initrd='/lkp/scheduled/vm-lkp-wsx03-openwrt-i386-5/trinity-300s-openwrt-i386-2016-03-16.cgz-c470abd4fde40ea6a0846a2beab642a578c0b8cd-20171109-63433-kf9gj3-wait_kernel-0.cgz'

[ -n "$LKP_SRC" ] ||
export LKP_SRC=/lkp/${user:-lkp}/src
}

run_job()
{
echo $$ > $TMP/run-job.pid

. $LKP_SRC/lib/http.sh
. $LKP_SRC/lib/job.sh
. $LKP_SRC/lib/env.sh

export_top_env

run_monitor $LKP_SRC/monitors/wrapper kmsg
run_monitor $LKP_SRC/monitors/wrapper oom-killer
run_monitor $LKP_SRC/monitors/plain/watchdog

run_test $LKP_SRC/tests/wrapper trinity
}

extract_stats()
{
$LKP_SRC/stats/wrapper kmsg

$LKP_SRC/stats/wrapper time trinity.time
$LKP_SRC/stats/wrapper time
$LKP_SRC/stats/wrapper dmesg
$LKP_SRC/stats/wrapper kmsg
$LKP_SRC/stats/wrapper stderr
$LKP_SRC/stats/wrapper last_state
}

"$@"