From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42473) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a756w-00028t-Nm for qemu-devel@nongnu.org; Thu, 10 Dec 2015 12:34:35 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1a756u-0004q9-1f for qemu-devel@nongnu.org; Thu, 10 Dec 2015 12:34:34 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60868) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1a756t-0004pw-S0 for qemu-devel@nongnu.org; Thu, 10 Dec 2015 12:34:31 -0500 References: <20151210140404.GA3049@nazgul.tnic> <20151210162733.GA6587@pd.tnic> <20151210164407.GA3593@nazgul.tnic> <5669AD06.3030409@redhat.com> <20151210165340.GA3831@pd.tnic> From: Paolo Bonzini Message-ID: <5669B79E.4000906@redhat.com> Date: Thu, 10 Dec 2015 18:34:22 +0100 MIME-Version: 1.0 In-Reply-To: <20151210165340.GA3831@pd.tnic> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] freeze host when injecting NMIs in the guest, at least in 4.4-rc4+ List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Borislav Petkov Cc: lkml , kvm@vger.kernel.org, qemu-devel@nongnu.org On 10/12/2015 17:53, Borislav Petkov wrote: > Just did, there it splats even when booting the guest, without even > injecting NMIs: > > [ 113.233992] =============================== > [ 113.238192] [ INFO: suspicious RCU usage. ] > [ 113.242393] 4.4.0-rc4+ #1 Not tainted > [ 113.246056] ------------------------------- > [ 113.250257] arch/x86/kvm/trace.h:29 suspicious rcu_dereference_check() usage! > [ 113.257400] > other info that might help us debug this: > > [ 113.265432] > RCU used illegally from idle CPU! > rcu_scheduler_active = 1, debug_locks = 0 > [ 113.276321] RCU used illegally from extended quiescent state! > [ 113.282083] 1 lock held by qemu-system-x86/2275: > [ 113.286711] #0: (&vcpu->mutex){+.+.+.}, at: [] vcpu_load+0x1c/0x80 [kvm] > [ 113.295270] > stack backtrace: > [ 113.299644] CPU: 4 PID: 2275 Comm: qemu-system-x86 Not tainted 4.4.0-rc4+ #1 > [ 113.306706] Hardware name: Dell Inc. Precision T3600/0PTTT9, BIOS A13 05/11/2014 > [ 113.314122] 0000000000000001 ffff88042f263d28 ffffffff813c2cfc ffff880432d53000 > [ 113.321575] ffff88042f263d58 ffffffff810c5157 ffff88042f268000 0000000000000000 > [ 113.329027] 0000000000000000 0000000000000001 ffff88042f263e10 ffffffffa01ee7c8 > [ 113.336483] Call Trace: > [ 113.338939] [] dump_stack+0x4e/0x82 > [ 113.344098] [] lockdep_rcu_suspicious+0xe7/0x120 > [ 113.350385] [] kvm_arch_vcpu_ioctl_run+0x16f8/0x19c0 [kvm] > [ 113.357544] [] ? kvm_arch_vcpu_ioctl_run+0xd0/0x19c0 [kvm] > [ 113.364695] [] kvm_vcpu_ioctl+0x342/0x700 [kvm] > [ 113.370896] [] ? __lock_is_held+0x4d/0x70 > [ 113.376583] [] ? __fget+0xfe/0x200 > [ 113.381662] [] do_vfs_ioctl+0x301/0x550 > [ 113.387156] [] ? __fget_light+0x2a/0x90 > [ 113.392654] [] SyS_ioctl+0x41/0x70 > [ 113.397739] [] entry_SYSCALL_64_fastpath+0x16/0x7a > [ 113.755008] kvm: zapping shadow pages for mmio generation wraparound Wow, this must have been there forever... Paolo