From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Aneesh Kumar K.V" Date: Wed, 15 Oct 2014 17:40:45 +0000 Subject: lockdep warning with 2d65a9f48fcdf7866aab6457bc707ca233e0c791 Message-Id: <87d29tkzsi.fsf@linux.vnet.ibm.com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: "kvm-ppc@vger.kernel.org" , Paul Mackerras , linuxppc-dev ======================[ INFO: possible recursive locking detected ] 3.17.0+ #31 Not tainted --------------------------------------------- qemu-system-ppc/9112 is trying to acquire lock: (&(&vcpu->arch.tbacct_lock)->rlock){......}, at: [] .vcore_stolen_time+0x44/0xb0 [kvm_hv] but task is already holding lock: (&(&vcpu->arch.tbacct_lock)->rlock){......}, at: [] .kvmppc_remove_runnable.part.2+0x34/0xd0 [kvm_hv] other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&(&vcpu->arch.tbacct_lock)->rlock); lock(&(&vcpu->arch.tbacct_lock)->rlock); *** DEADLOCK *** May be due to missing lock nesting notation 3 locks held by qemu-system-ppc/9112: #0: (&vcpu->mutex){+.+.+.}, at: [] .vcpu_load+0x2c/0xf0 #1: (&(&vcore->lock)->rlock){+.+...}, at: [] .kvmppc_vcpu_run_hv+0x770/0x1720 [kvm_hv] #2: (&(&vcpu->arch.tbacct_lock)->rlock){......}, at: [] .kvmppc_remove_runnable.part.2+0x34/0xd0 [kvm_hv] stack backtrace: CPU: 56 PID: 9112 Comm: qemu-system-ppc Not tainted 3.17.0+ #31 Call Trace: [c000000fe488f330] [c0000000000167dc] .show_stack+0x7c/0x1f0 (unreliable) [c000000fe488f400] [c0000000008ea148] .dump_stack+0x9c/0xd8 [c000000fe488f480] [c000000000110c6c] .__lock_acquire+0x151c/0x1ef0 [c000000fe488f600] [c000000000111fb0] .lock_acquire+0xd0/0x1b0 [c000000fe488f6d0] [c0000000008ddedc] ._raw_spin_lock_irq+0x5c/0x80 [c000000fe488f760] [d000000011591f84] .vcore_stolen_time+0x44/0xb0 [kvm_hv] [c000000fe488f7f0] [d00000001159253c] .kvmppc_remove_runnable.part.2+0x4c/0xd0 [kvm_hv] [c000000fe488f890] [d0000000115950c0] .kvmppc_vcpu_run_hv+0x10a0/0x1720 [kvm_hv] [c000000fe488f9f0] [c000000000091d1c] .kvmppc_vcpu_run+0x2c/0x40 [c000000fe488fa60] [c00000000008efd4] .kvm_arch_vcpu_ioctl_run+0x54/0x170 [c000000fe488faf0] [c000000000086f78] .kvm_vcpu_ioctl+0x5c8/0x780 [c000000fe488fcb0] [c000000000264b54] .do_vfs_ioctl+0x474/0x770 [c000000fe488fd90] [c000000000264ea8] .SyS_ioctl+0x58/0xb0 [c000000fe488fe30] [c000000000009264] syscall_exit+0x0/0x98