On 2015/7/3 19:23, Paolo Bonzini wrote:
On 03/07/2015 10:56, Tiejun Chen wrote:After commit 1cde2930e154 ("sched/preempt: Add static_key() to preempt_notifiers") is introduced, preempt_notifier_{register, unregister} always hold a mutex, jump_label_mutex. So in current case this shouldn't work further under the circumstance of disabled preemption, and its also safe since we're just handling a per-vcpu stuff with holding vcpu->mutex. Otherwise, some warning messages are posted like this,BUG: scheduling while atomic: qemu-system-x86/17177/0x00000002 2 locks held by qemu-system-x86/17177: #0: (&vcpu->mutex){+.+.+.}, at: [<ffffffffa035fb48>] vcpu_load+0x28/0xf0 [kvm] #1: (jump_label_mutex){+.+.+.}, at: [<ffffffff81244b54>] static_key_slow_inc+0xc4/0x140 Modules linked in: x86_pkg_temp_thermal kvm_intel kvm Preemption disabled at:[<ffffffffa035fd3e>] kvm_vcpu_ioctl+0x7e/0xeb0 [kvm]Thanks for your work Tiejun. However, the original patch is crap. I've asked to revert it.
Yeah, its better to revert that commit since finally this also trigger a bug 100671: vmwrite error in vmx_vcpu_run.
Thanks Tiejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
