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. 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
