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

[Коренберг Марк]

I have tried to repeat this bug on latest snapshot of kvm, and kvm get fall  in 
same places.
I talked with Jan Kiszka. bt commands on three experiments in same conditions:

-------------------------------------------------
(gdb) bt
#0  0xb7412500 in main_arena () from /lib/tls/i686/cmov/libc.so.6
#1  0x080b1a36 in scsi_write_complete (opaque=0x9f4bef0, ret=0) at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/hw/scsi-disk.c:231
#2  0x08095281 in qcow_aio_write_cb (opaque=0x9fef530, ret=0) at 
block/qcow2.c:640
#3  0x080849bf in posix_aio_process_queue (opaque=0x9ddb798) at 
posix-aio-compat.c:460
#4  0x08084a77 in posix_aio_read (opaque=0x9ddb798) at posix-aio-compat.c:501
#5  0x0805e3d8 in main_loop_wait (nonblocking=0) at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/vl.c:1300
#6  0x0806ea84 in kvm_main_loop () at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/qemu-kvm.c:1710
#7  0x08060a73 in main_loop (argc=14, argv=0xbf959ef4, envp=0xbf959f30) at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/vl.c:1340
#8  main (argc=14, argv=0xbf959ef4, envp=0xbf959f30) at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/vl.c:3069
-------------------------------------------------
(gdb) bt
#0  0xb7778430 in __kernel_vsyscall ()
#1  0xb7309651 in *__GI_raise (sig=6) at 
../nptl/sysdeps/unix/sysv/linux/raise.c:64
#2  0xb730ca82 in *__GI_abort () at abort.c:92
#3  0xb734049d in __libc_message (do_abort=2, fmt=0xb7414f98 "*** glibc 
detected *** %s: %s: 0x%s ***\n")   at ../sysdeps 
unix/sysv/linux/libc_fatal.c:189
#4  0xb734a591 in malloc_printerr (action=<value optimized out>, str=0x6 
<Address 0x6 out of bounds>, ptr=0x9aca398) at malloc.c:6264
#5  0xb734bde8 in _int_free (av=<value optimized out>, p=<value optimized out>) 
at malloc.c:4792
#6  0xb734eecd in *__GI___libc_free (mem=0x9aca398) at malloc.c:3738
#7  0x080b186c in scsi_remove_request (r=0x9aca398) at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/hw/scsi-disk.c:86
#8  0x08095281 in qcow_aio_write_cb (opaque=0x9abee58, ret=0) at 
block/qcow2.c:640
#9  0x080849bf in posix_aio_process_queue (opaque=0x994e798) at 
posix-aio-compat.c:460
#10 0x08084a77 in posix_aio_read (opaque=0x994e798) at posix-aio-compat.c:501
#11 0x0805e3d8 in main_loop_wait (nonblocking=0) at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/vl.c:1300
#12 0x0806ea84 in kvm_main_loop () at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/qemu-kvm.c:1710
#13 0x08060a73 in main_loop (argc=14, argv=0xbffb66e4, envp=0xbffb6720) at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/vl.c:1340
#14 main (argc=14, argv=0xbffb66e4, envp=0xbffb6720) at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/vl.c:3069
--------------------------------------------------------
#0  0x08d134f0 in ?? ()
#1  0x080b1936 in scsi_command_complete (r=0x8d083f0, status=<value optimized 
out>, sense=<value optimized out>) at 
home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/hw/scsi-disk.c:106
#2  0x08095281 in qcow_aio_write_cb (opaque=0x8dab488, ret=0) at 
block/qcow2.c:640
#3  0x080849bf in posix_aio_process_queue (opaque=0x8b97798) at 
posix-aio-compat.c:460
#4  0x08084a77 in posix_aio_read (opaque=0x8b97798) at posix-aio-compat.c:501
#5  0x0805e3d8 in main_loop_wait (nonblocking=0) at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/vl.c:1300
#6  0x0806ea84 in kvm_main_loop () at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/qemu-kvm.c:1710
#7  0x08060a73 in main_loop (argc=14, argv=0xbffa54e4, envp=0xbffa5520) at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/vl.c:1340
#8  main (argc=14, argv=0xbffa54e4, envp=0xbffa5520) at 
/home/mmarkk/src/KVM/Latest/qemu-kvm-d4adede/vl.c:3069
-------------------------------------------------


** Changed in: qemu
       Status: New => Confirmed

-- 
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.