On 2011-02-23 16:53, Ryousei Takano wrote:
> Hi Jan,
>
> On Wed, Feb 23, 2011 at 11:47 PM, Jan Kiszka <jan.kiszka@xxxxxxxxxxx> wrote:
>> On 2011-02-23 15:38, Ryousei Takano wrote:
>>> This reverts commit c65827770b5e7282b5fb9da29c1de85ed08e816e
>>
>> Reasoning would belong here, not below the separator.
>>
>>>
>>> Signed-off-by: Ryousei Takano <takano-ryousei@xxxxxxxxxx>
>>> ---
>>> I am trying to run OpenMP (i.e., multi-threaded) programs using Intel
>>> Math Kernel Library (MKL) on a guest OS. In the qemu-kvm-0.12.5,
>>> my program works fine. In the qemu-kvm-0.13.0, however, it does not.
>>
>> What about 0.14?
>>
> 0.14-rc1 also has problem.
Not automagically healed - what a pity.
>
>>> The Linux kernel is 2.6.32.28. The outputs of 'ps -L' are shown as follows:
>>>
>>> qemu-kvm-0.12.5:
>>> PID LWP TTY TIME CMD
>>> 2731 2731 pts/0 00:00:00 bash
>>> 2799 2799 pts/0 00:00:19 a.out
>>> 2799 2803 pts/0 00:00:00 a.out
>>> 2799 2804 pts/0 00:00:04 a.out <-
>>> 2799 2805 pts/0 00:00:03 a.out <- these threads are working properly.
>>> 2799 2806 pts/0 00:00:04 a.out <-
>>> 2807 2807 pts/0 00:00:00 ps
>>>
>>> qemu-0.13.0:
>>> PID LWP TTY TIME CMD
>>> 2725 2725 pts/0 00:00:00 bash
>>> 2748 2748 pts/0 00:00:19 a.out
>>> 2748 2752 pts/0 00:00:00 a.out
>>> 2748 2753 pts/0 00:00:00 a.out <-
>>> 2748 2754 pts/0 00:00:00 a.out <- these threads are blocked by
>>> pthread_cond_wait(3).
>>> 2748 2755 pts/0 00:00:00 a.out <-
>>> 2756 2756 pts/0 00:00:00 ps
>>>
>>> This problem seems to be introduced by the commit
>>> c65827770b5e7282b5fb9da29c1de85ed08e816e.
>>> The attached revert patch solves it. But I do not understand what is
>>> happened;-)
>>> Any comments and suggestions will be appreciated.
>>>
>>> Regards,
>>> Ryousei
>>>
>>> hw/pc.c | 6 ++++++
>>> target-i386/helper.c | 2 --
>>> 2 files changed, 6 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/hw/pc.c b/hw/pc.c
>>> index ec97181..577abe7 100644
>>> --- a/hw/pc.c
>>> +++ b/hw/pc.c
>>> @@ -937,6 +937,12 @@ CPUState *pc_new_cpu(const char *cpu_model)
>>> }
>>> qemu_register_reset(pc_cpu_reset, env);
>>> pc_cpu_reset(env);
>>> +
>>> + /* kvm needs this to run after the apic is initialized. Otherwise,
>>> + * it can access invalid state and crash.
>>> + */
>>> + qemu_init_vcpu(env);
>>> +
>>> return env;
>>> }
>>>
>>> diff --git a/target-i386/helper.c b/target-i386/helper.c
>>> index 86202e6..69cda5e 100644
>>> --- a/target-i386/helper.c
>>> +++ b/target-i386/helper.c
>>> @@ -1224,8 +1224,6 @@ CPUX86State *cpu_x86_init(const char *cpu_model)
>>> }
>>> mce_init(env);
>>>
>>> - qemu_init_vcpu(env);
>>> -
>>> return env;
>>> }
>>>
>>
>> I don't believe yet that the patch is the reason, specifically as it
>> targets the setup phase (except for CPU hotplug, but that's broken for
>> ages), not the operational phase of the VM.
>>
>> What's your qemu-kvm command line?
>>
> Here is my command line.
>
> sudo qemu-system-x86_64 \
> -cpu host \
> -smp 8 \
> -m 46080 \
> -net nic,model=virtio,macaddr=00:16:3e:1d:ff:00 \
> -net tap,ifname=tap0,script=no,downscript=no \
> -monitor telnet::5963,server,nowait \
> -daemonize \
> disk.img
How many cores are available on the host? >= 8 or less?
>
>> Also, please attach gdb to the stuck VM and print the backtraces of all
>> threads ("thread apply all bt").
>>
> (gdb) thread apply all bt
> Thread 9 (Thread 0x41129940 (LWP 8118)):
> #0 0x0000003dd38cc647 in ioctl () from /lib64/libc.so.6
> #1 0x000000000042e56d in pthread_attr_setdetachstate ()
> #2 0x000000000042ea99 in pthread_attr_setdetachstate ()
> #3 0x000000000042ecf0 in pthread_attr_setdetachstate ()
> #4 0x0000003dd400673d in start_thread () from /lib64/libpthread.so.0
> #5 0x0000003dd38d3d1d in clone () from /lib64/libc.so.6
>
> Thread 8 (Thread 0x41ca8940 (LWP 8119)):
> #0 0x0000003dd38cc647 in ioctl () from /lib64/libc.so.6
> #1 0x000000000042e56d in pthread_attr_setdetachstate ()
> #2 0x000000000042ea99 in pthread_attr_setdetachstate ()
> #3 0x000000000042ecf0 in pthread_attr_setdetachstate ()
> #4 0x0000003dd400673d in start_thread () from /lib64/libpthread.so.0
> #5 0x0000003dd38d3d1d in clone () from /lib64/libc.so.6
>
> Thread 7 (Thread 0x425f2940 (LWP 8120)):
> #0 0x0000003dd38cc647 in ioctl () from /lib64/libc.so.6
> #1 0x000000000042e56d in pthread_attr_setdetachstate ()
> #2 0x000000000042ea99 in pthread_attr_setdetachstate ()
> #3 0x000000000042ecf0 in pthread_attr_setdetachstate ()
> #4 0x0000003dd400673d in start_thread () from /lib64/libpthread.so.0
> #5 0x0000003dd38d3d1d in clone () from /lib64/libc.so.6
>
> Thread 6 (Thread 0x42df3940 (LWP 8121)):
> #0 0x0000003dd38cc647 in ioctl () from /lib64/libc.so.6
> #1 0x000000000042e56d in pthread_attr_setdetachstate ()
> #2 0x000000000042ea99 in pthread_attr_setdetachstate ()
> #3 0x000000000042ecf0 in pthread_attr_setdetachstate ()
> #4 0x0000003dd400673d in start_thread () from /lib64/libpthread.so.0
> #5 0x0000003dd38d3d1d in clone () from /lib64/libc.so.6
>
> Thread 5 (Thread 0x435f4940 (LWP 8122)):
> #0 0x0000003dd38cc647 in ioctl () from /lib64/libc.so.6
> #1 0x000000000042e56d in pthread_attr_setdetachstate ()
> #2 0x000000000042ea99 in pthread_attr_setdetachstate ()
> #3 0x000000000042ecf0 in pthread_attr_setdetachstate ()
> #4 0x0000003dd400673d in start_thread () from /lib64/libpthread.so.0
> #5 0x0000003dd38d3d1d in clone () from /lib64/libc.so.6
>
> Thread 4 (Thread 0x43df5940 (LWP 8123)):
> #0 0x0000003dd38cc647 in ioctl () from /lib64/libc.so.6
> #1 0x000000000042e56d in pthread_attr_setdetachstate ()
> #2 0x000000000042ea99 in pthread_attr_setdetachstate ()
> #3 0x000000000042ecf0 in pthread_attr_setdetachstate ()
> #4 0x0000003dd400673d in start_thread () from /lib64/libpthread.so.0
> #5 0x0000003dd38d3d1d in clone () from /lib64/libc.so.6
>
> Thread 3 (Thread 0x445f6940 (LWP 8124)):
> #0 0x0000003dd38cc647 in ioctl () from /lib64/libc.so.6
> #1 0x000000000042e56d in pthread_attr_setdetachstate ()
> #2 0x000000000042ea99 in pthread_attr_setdetachstate ()
> #3 0x000000000042ecf0 in pthread_attr_setdetachstate ()
> #4 0x0000003dd400673d in start_thread () from /lib64/libpthread.so.0
> #5 0x0000003dd38d3d1d in clone () from /lib64/libc.so.6
>
> Thread 2 (Thread 0x44df7940 (LWP 8125)):
> #0 0x0000003dd38cc647 in ioctl () from /lib64/libc.so.6
> #1 0x000000000042e56d in pthread_attr_setdetachstate ()
> #2 0x000000000042ea99 in pthread_attr_setdetachstate ()
> #3 0x000000000042ecf0 in pthread_attr_setdetachstate ()
> #4 0x0000003dd400673d in start_thread () from /lib64/libpthread.so.0
> #5 0x0000003dd38d3d1d in clone () from /lib64/libc.so.6
>
> Thread 1 (Thread 0x7fe796ec1740 (LWP 8117)):
> #0 0x0000003dd38ccfc2 in select () from /lib64/libc.so.6
> #1 0x0000000000419620 in pthread_attr_setdetachstate ()
> #2 0x000000000042be07 in pthread_attr_setdetachstate ()
> #3 0x000000000041ae20 in pthread_attr_setdetachstate ()
> #4 0x0000003dd381d994 in __libc_start_main () from /lib64/libc.so.6
> #5 0x00000000004063d9 in pthread_attr_setdetachstate ()
> #6 0x00007fff8050c988 in ?? ()
> #7 0x0000000000000000 in ?? ()
>
Can you retry with --enable-debug set during qemu-kvm configure? We need
the symbols of the qemu functions. Despite the lacking symbols, this
rather looks like we are stuck in kernel space, not on some condition
variable (ie. futex).
Then probably also interesting would be a trace of the host kernel
(trace-cmd record -e kvm, see e.g. [1]).
Thanks,
Jan
[1] http://lwn.net/Articles/341902/
--
Siemens AG, Corporate Technology, CT T DE IT 1
Corporate Competence Center Embedded Linux
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