Bug 1278282

Summary: memory unplug triggers BUG_ON: kernel BUG at mm/memory_hotplug.c:703!
Product: Red Hat Enterprise Linux 7 Reporter: Jan Kurik <jkurik>
Component: qemu-kvm-rhevAssignee: Igor Mammedov <imammedo>
Status: CLOSED ERRATA QA Contact: Virtualization Bugs <virt-bugs>
Severity: unspecified Docs Contact:
Priority: unspecified    
Version: 7.2CC: hhuang, huding, imammedo, jkurik, juzhang, knoel, lmiksik, mrezanin, ovasik, sherold, tlavigne, virt-maint, xfu, yuhuang
Target Milestone: rcKeywords: ZStream
Target Release: ---   
Hardware: Unspecified   
OS: Unspecified   
Whiteboard:
Fixed In Version: qemu-kvm-rhev-2.3.0-31.el7_2.1 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: 1275230 Environment:
Last Closed: 2015-12-07 21:42:33 UTC Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:
Bug Depends On: 1275230    
Bug Blocks:    

Description Jan Kurik 2015-11-05 07:27:36 UTC
This bug has been copied from bug #1275230 and has been proposed
to be backported to 7.2 z-stream (EUS).

Comment 4 Yumei Huang 2015-11-11 06:27:27 UTC
Reproduce:
kernel: 3.10.0-326.el7.x86_64
qemu:qemu-kvm-rhev-2.3.0-31.el7

Steps:
1. /usr/libexec/qemu-kvm -name rhel72-sn5 -m 4G,slots=8,maxmem=40G -smp 4,sockets=4,cores=1,threads=1 -no-user-config -nodefaults -rtc base=utc,driftfix=slew -global kvm-pit.lost_tick_policy=discard -boot menu=on,strict=on -object iothread,id=iothread0 -drive file=/home/guest/rhel72-sn5.img,if=none,id=drive-data-disk,format=qcow2,cache=none,aio=native,werror=stop,rerror=stop  -device virtio-blk-pci,drive=drive-data-disk,id=data-disk,iothread=iothread0,bus=pci.0,addr=0x7 -netdev tap,id=hostnet1,vhost=on -device e1000,netdev=hostnet1,id=net2,mac=10:1a:4a:42:0a:0b,bus=pci.0,addr=0xa -usb -device usb-tablet,id=input0 -vga qxl -spice port=5901,addr=0.0.0.0,disable-ticketing,image-compression=off,seamless-migration=on -monitor unix:/tmp/monitor3,server,nowait -serial unix:/tmp/console,server,nowait

2. Hotplug memory 5 times via script 
#!/bin/bash 
i=0 
while [ $i -lt 5 ] 
do 
echo $i 
sleep 3 
echo "object_add memory-backend-ram,id=mem$i,size=128M"|nc -U /tmp/monitor3 
sleep 2 
echo "device_add pc-dimm,id=dimm$i,memdev=mem$i,slot=$i"|nc -U /tmp/monitor3 
i=$(($i+1)) 
done 

3. Unplug memory 5 times via script; 
#!/bin/bash
i=0
while [ $i -lt 5 ]
do
echo $i
sleep 3
echo "device_del dimm$i"|nc -U /tmp/monitor3
echo "object_del mem$i"|nc -U /tmp/monitor3
sleep 2
i=$(($i+1))
done 

Guest crashed.Got same result "kernel BUG at mm/memory_hotplug.c:703!"

Verify:
kernel: 3.10.0-328.el7.x86_64
qemu: qemu-kvm-rhev-2.3.0-31.el7_2.1

With same steps as above, guest work well, don't crash. 

So the bug is fixed.

Comment 5 Yumei Huang 2015-11-16 04:35:12 UTC
Reverify:
kernel: 3.10.0-327.2.1.el7.x86_64
qemu-kvm: qemu-kvm-rhev-2.3.0-31.el7_2.1

With same steps as comment 4, guest works well, don't crash. 
So,the bug is fixed.

Comment 6 Yumei Huang 2015-11-19 08:33:50 UTC
Reverify:
kernel: 3.10.0-331.el7.x86_64
qemu-kvm: qemu-kvm-rhev-2.3.0-31.el7_2.2

QE test on above environment with same steps as comment 4, guest works well, don't crash. 
So the bug is fixed.

Comment 7 Yumei Huang 2015-11-23 06:56:57 UTC
Reverify:
kernel: 3.10.0-327.3.1.el7.x86_64
qemu-kvm: qemu-kvm-rhev-2.3.0-31.el7_2.3

QE test on above environment with same steps as comment 4, guest works well, don't crash. 
So the bug is fixed.

Comment 12 errata-xmlrpc 2015-12-07 21:42:33 UTC
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2015-2555.html