On Mon, Oct 26, 2009 at 04:46:02PM -0200, Marcelo Tosatti wrote:
>
> Michael reported a qemu-kvm SIGSEGV at shutdown:
>
> Program received signal SIGSEGV, Segmentation fault.
> [Switching to Thread 0x411d0940 (LWP 14446)]
> 0x000000000040afb4 in qemu_mod_timer (ts=0x19f0fd0,
> expire_time=62275467335)
> at /home/mst/scm/qemu-kvm/vl.c:1009
> 1009 if ((alarm_timer->flags & ALARM_FLAG_EXPIRED) == 0)
> {
> (gdb) l
> 1004 ts->next = *pt;
> 1005 *pt = ts;
> 1006
> 1007 /* Rearm if necessary */
> 1008 if (pt == &active_timers[ts->clock->type]) {
> 1009 if ((alarm_timer->flags & ALARM_FLAG_EXPIRED) == 0)
> {
> 1010 qemu_rearm_alarm_timer(alarm_timer);
> 1011 }
> 1012 /* Interrupt execution to force deadline
> recalculation. */
> 1013 if (use_icount)
> (gdb) p alarm_timer
> $1 = (struct qemu_alarm_timer *) 0x0
>
> Problem is kvm_main_loop_wait(env, 0) can process the stop request
> (signalling iothread that vcpu is stopped, so its OK to exit) and
> continue to kvm_cpu_exec.
>
> Make sure cpu is not stopped before proceeding to kvm_cpu_exec.
>
> Signed-off-by: Marcelo Tosatti <[email protected]>
> Reported-by: "Michael S. Tsirkin" <[email protected]>
>
> diff --git a/qemu-kvm.c b/qemu-kvm.c
> index 4c13628..ab8f0e4 100644
> --- a/qemu-kvm.c
> +++ b/qemu-kvm.c
> @@ -1868,7 +1868,8 @@ static int kvm_main_loop_cpu(CPUState *env)
> }
> if (run_cpu) {
> kvm_main_loop_wait(env, 0);
> - kvm_cpu_exec(env);
> + if (!is_cpu_stopped(env))
> + kvm_cpu_exec(env);
I wonder if calling kvm_cpu_exec() after kvm_main_loop_wait() will fix
the problem?
> } else {
> kvm_main_loop_wait(env, 1000);
> }
> --
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--
Gleb.
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