Am 08.11.2010 10:18, Markus Trippelsdorf wrote: > On Mon, Nov 08, 2010 at 10:04:00AM +0100, Jan Kiszka wrote: >> Hi, >> >> I'm seeing lock-ups of the QEMU process on kvm.git as well as current >> upstream kernels. This is a backtrace of the hanging VCPU thread: >> >> [<ffffffff810a27bc>] __stop_cpus+0x184/0x1a7 >> [<ffffffff810a286f>] try_stop_cpus+0x40/0x59 >> [<ffffffff8103a30c>] synchronize_sched_expedited+0x84/0x9d >> [<ffffffff810715a3>] __synchronize_srcu+0x33/0x72 >> [<ffffffff810715f7>] synchronize_srcu_expedited+0x15/0x17 >> [<ffffffffa06602ae>] __kvm_set_memory_region+0x6a3/0x782 [kvm] >> [<ffffffffa06603c4>] kvm_set_memory_region+0x37/0x50 [kvm] >> [<ffffffffa0661c30>] kvm_vm_ioctl_set_memory_region+0x18/0x1a [kvm] >> [<ffffffffa0661e5f>] kvm_vm_ioctl+0x22d/0x3b1 [kvm] >> [<ffffffff81143c26>] do_vfs_ioctl+0x5a1/0x5e2 >> [<ffffffff81143cbd>] sys_ioctl+0x56/0x79 >> [<ffffffff81002df2>] system_call_fastpath+0x16/0x1b >> [<ffffffffffffffff>] 0xffffffffffffffff >> >> This issue disappears when disabling CONFIG_PREEMPT on the host. >> According to some rough bisecting, it was imported into kvm.git with >> merge 146d3bb06b. Given that RCU is involved, I also tried >> force-enabling non-preemptible CONFIG_TREE_RCU again, but that made no >> difference as long as PREEMPT is on. >> >> Can anyone confirm this or does someone have an idea what goes wrong? Of >> course, .config will be provided if required. > > This patch should help (,it fixes the problem in my case): > http://article.gmane.org/gmane.linux.kernel/1058018 Yeah, that works here as well. Would be a nice-to-have in kvm.git until it's pull via the next upstream merge. At least for me this bug triggers at every VM boot. Jan -- Siemens AG, Corporate Technology, CT T DE IT 1 Corporate Competence Center Embedded Linux -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
