[Qemu-devel] [Bug 595438] Re: KVM segmentation fault, using SCSI+writeback and linux 2.4 guest

[Коренберг Марк]

New links:

http://dl3.ideco-software.ru/IdecoICS/IdecoICS_343_102.iso
http://dl1.ideco-software.ru/IdecoICS/IdecoICS_343_102.iso
http://dl2.ideco-software.ru/IdecoICS/IdecoICS_343_102.iso

For some reason the fall of KVM are much rarer, though earlier it fell
each time. I noticed that more often than not, it crashes when KVM is in
the background, and I say, sitting in the browser. It seems, that it is
true race-condition.

$ ./kvm --version
QEMU emulator version 0.12.50 (qemu-kvm-devel), Copyright (c) 2003-2008 Fabrice 
Bellard

Also, I have checked - cache=writeback does not work not in ide, nor in
scsi. I mean that write cache does not work, and writing work as
writethrough. In old version of KVM (qemu-kvm-0.12.3) there is no such
bug.

-- 
KVM segmentation fault, using SCSI+writeback and linux 2.4 guest
https://bugs.launchpad.net/bugs/595438
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Status in QEMU: Confirmed

Bug description:
I Use Ubuntu 32 bit 10.04 with standard KVM.
I have Intel E7600  @ 3.06GHz processor with VMX

In this system I Run:
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin 
QEMU_AUDIO_DRV=none /usr/bin/kvm -M pc-0.12 -enable-kvm -m 256 -smp 1 -name 
spamsender -uuid b9cacd5e-08f7-41fd-78c8-89cec59af881 -chardev 
socket,id=monitor,path=/var/lib/libvirt/qemu/spamsender.monitor,server,nowait 
-monitor chardev:monitor -boot d -drive 
file=/mnt/megadiff/cdiso_400_130.iso,if=ide,media=cdrom,index=2 -drive 
file=/home/mmarkk/spamsender2.img,if=scsi,index=0,format=qcow2,cache=writeback 
-net nic,macaddr=00:00:00:00:00:00,vlan=0,name=nic.0 -net tap,vlan=0,name=tap.0 
-chardev pty,id=serial0 -serial chardev:serial0 -parallel none -usb -vnc 
127.0.0.1:0 -vga cirrus

.iso image contain custom distro of 2.4-linux kernel based system. During 
install process (when .tar.gz actively unpacked), kvm dead with segmentation 
fault.

And ONLY when I choose scsi virtual disk and writeback simultaneously. 
But, writeback+ide, writethrough+scsi works OK.

I use qcow2. It seems, that qcow does not have such problems.

Virtual machine get down at random time during file copy. It seems, when qcow2 
file size need to be expanded.