On 01/14/2013 01:24 PM, Andrew Clayton wrote:
On Mon, 14 Jan 2013 15:27:36 +0200, Gleb Natapov wrote:
On Sun, Jan 13, 2013 at 10:29:58PM +0000, Andrew Clayton wrote:
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.
Can you run "echo t > /proc/sysrq-trigger" and see where it hangs?
Here you go, here's the bash process, qemu and a kvm bit. (From the
above command)
bash S ffff88013b2b0d00 0 3203 3133 0x00000000
ffff880114dabe58 0000000000000082 8000000113558065 ffff880114dabfd8
ffff880114dabfd8 0000000000004000 ffff88013b0c5b00 ffff88013b2b0d00
ffff880114dabd88 ffffffff8109067d ffffea0004536670 ffffea0004536640
Call Trace:
[<ffffffff8109067d>] ? default_wake_function+0xd/0x10
[<ffffffff8108a315>] ? atomic_notifier_call_chain+0x15/0x20
[<ffffffff8133d84f>] ? tty_get_pgrp+0x3f/0x50
[<ffffffff810819ac>] ? pid_vnr+0x2c/0x30
[<ffffffff8133fe54>] ? tty_ioctl+0x7b4/0xbd0
[<ffffffff8106bf62>] ? wait_consider_task+0x102/0xaf0
[<ffffffff815c00e4>] schedule+0x24/0x70
[<ffffffff8106cb24>] do_wait+0x1d4/0x200
[<ffffffff8106d9cb>] sys_wait4+0x9b/0xf0
[<ffffffff8106b9f0>] ? task_stopped_code+0x50/0x50
[<ffffffff815c1ad2>] system_call_fastpath+0x16/0x1b
qemu-kvm D ffff88011ab8c8b8 0 3345 3203 0x00000000
ffff880112129cd8 0000000000000082 ffff880112129c50 ffff880112129fd8
ffff880112129fd8 0000000000004000 ffff88013b04ce00 ffff880139da1a00
0000000000000000 00000000000280da ffff880112129d38 ffffffff810d3300
Call Trace:
[<ffffffff810d3300>] ? __alloc_pages_nodemask+0xf0/0x7c0
[<ffffffff811273c6>] ? touch_atime+0x66/0x170
[<ffffffff810cdabf>] ? generic_file_aio_read+0x5bf/0x730
[<ffffffff815c00e4>] schedule+0x24/0x70
[<ffffffff815c0cdd>] rwsem_down_failed_common+0xbd/0x150
[<ffffffff815c0da3>] rwsem_down_write_failed+0x13/0x15
[<ffffffff812d1be3>] call_rwsem_down_write_failed+0x13/0x20
[<ffffffff815bf4dd>] ? down_write+0x2d/0x34
[<ffffffff810f0724>] vma_adjust+0xe4/0x610
[<ffffffff810f0fa4>] vma_merge+0x1b4/0x270
[<ffffffff810f1fa6>] do_brk+0x196/0x330
[<ffffffff810f2217>] sys_brk+0xd7/0x130
[<ffffffff815c1ad2>] system_call_fastpath+0x16/0x1b
This looks like qemu-kvm getting stuck trying to get the anon_vma lock.
That leads to the obvious question: what is holding the lock, and/or
failed to release it?
Do you have any other (qemu-kvm?) processes on your system that have
any code in the VM (or strace/ptrace/...) in the backtrace, that might
be holding this lock?
Do you have anything in your dmesg showing threads that had a BUG_ON
(and exited) while holding the lock?
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