qemu-kvm hangs at start up under 3.8.0-rc3-00074-gb719f43 (workswith CONFIG_LOCKDEP)

[Andrew Clayton]

When running qemu-kvm under 64but Fedora 16 under current 3.8, it just
hangs at start up. Dong a ps -ef hangs the process at the point where it
would display the qemu process (trying to list the qemu-kvm /proc pid
directory contents just hangs ls).

I also noticed some other weirdness at this point like Firefox hanging
for many seconds at a time and increasing load average.

The qemu command I was trying to run was

$ qemu-kvm -m 512 -smp 2 -vga vmware -k en-gb -drive
file=/home/andrew/machines/qemu/f16-i386.img,if=virtio

Here's the last few lines of a strace on it at start up.

open("/home/andrew/machines/qemu/f16-i386.img", O_RDWR|O_DSYNC|O_CLOEXEC) = 8
lseek(8, 0, SEEK_END)                   = 9100722176
pread(8, "QFI\373\0\0\0\2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\20\0\0\0\2\200\0\0\0"..., 512, 0) = 512
pread(8, "\200\0\0\0\0\4\0\0\200\0\0\0\0\10\0\0\200\0\0\0\2\210\0\0\200\0\0\0\2\233\0\0"..., 512, 65536) = 512
brk(0)                                  = 0x7faf12db0000
brk(0x7faf12ddd000

It's hanging in that brk syscall. The load average also then starts to increase.


However. I can make it run fine, if I enable CONFIG_LOCKDEP. But the only
thing in dmesg I get is the usual.

kvm: SMP vm created on host with unstable TSC; guest TSC will not be reliable

I've attached both working and non-working .configs. The only difference being
the lock checking enabled in config.good.

The most recent kernel I had it working in was 3.7.0

System is a Quad Core Intel running 64bit Fedora 16.

Cheers,
Andrew

Attachment: config.bad.gz
Description: GNU Zip compressed data

Attachment: config.good.gz
Description: GNU Zip compressed data