Yes, we should add it at qmp_query_cpus_fast() . In this case, qmp_query_cpus() may kick a vcpu thread that has stopped causing the qemu process to exit, qmp_query_cpus_fast() does not interrupt vCPU threads, but may return invalid vCPU information.
> -----Original Message----- > From: Igor Mammedov [mailto:imamm...@redhat.com] > Sent: Wednesday, April 11, 2018 7:46 PM > To: linzhecheng <linzhech...@huawei.com> > Cc: qemu-devel@nongnu.org; xuyandong <xuyando...@huawei.com>; > pbonz...@redhat.com; wangxin (U) <wangxinxin.w...@huawei.com>; > r...@twiddle.net; crosthwaite.pe...@gmail.com > Subject: Re: [Qemu-devel] [PATCH] cpu: skip unpluged cpu when querying > cpus > > On Wed, 11 Apr 2018 19:16:02 +0800 > linzhecheng <linzhech...@huawei.com> wrote: > > > From: XuYandong <xuyando...@huawei.com> > > > > After vcpu1 thread exiting, vcpu0 thread (received notification) is > > still waiting for holding qemu_global_mutex in cpu_remove_sync, at this > moment, vcpu1 is still in global cpus list. > > If main thread grab qemu_global_mutex in order to handle qmp command > > "info cpus", qmp_query_cpus visit unpluged vcpu1 will lead qemu process > to exit. > Add here exact error or better stack trace in case it crashes. > > > > Signed-off-by: XuYandong <xuyando...@huawei.com> > > --- > > cpus.c | 5 +++++ > > 1 file changed, 5 insertions(+) > > > > diff --git a/cpus.c b/cpus.c > > index 2cb0af9..9b3a6c4 100644 > > --- a/cpus.c > > +++ b/cpus.c > > @@ -2018,6 +2018,11 @@ CpuInfoList *qmp_query_cpus(Error **errp) > > > > CPU_FOREACH(cpu) { > > CpuInfoList *info; > > + > > + if (cpu->unplug) { > > + continue; > > + } > Shouldn't be it done for qmp_query_cpus_fast() as well? > > > + > > #if defined(TARGET_I386) > > X86CPU *x86_cpu = X86_CPU(cpu); > > CPUX86State *env = &x86_cpu->env;
