On Wed, Apr 21, 2010 at 11:17:22AM +0300, Avi Kivity wrote: > On 04/21/2010 01:21 AM, Paul E. McKenney wrote: > > > >>Subject: [PATCH] kvm: add missing srcu_read_lock() > >> > >>I got this dmesg due to srcu_read_lock() is missing in > >>kvm_mmu_notifier_release(). > >> > >>=================================================== > >>[ INFO: suspicious rcu_dereference_check() usage. ] > >>--------------------------------------------------- > >>arch/x86/kvm/x86.h:72 invoked rcu_dereference_check() without protection! > >> > >>other info that might help us debug this: > >> > >> > >>rcu_scheduler_active = 1, debug_locks = 0 > >>2 locks held by qemu-system-x86/3100: > >> #0: (rcu_read_lock){.+.+..}, at: [<ffffffff810d73dc>] __mmu_notifier_release+0x38/0xdf > >> #1: (&(&kvm->mmu_lock)->rlock){+.+...}, at: [<ffffffffa0130a6a>] kvm_mmu_zap_all+0x21/0x5e [kvm] > >> > >>stack backtrace: > >>Pid: 3100, comm: qemu-system-x86 Not tainted 2.6.34-rc3-22949-gbc8a97a-dirty #2 > >>Call Trace: > >> [<ffffffff8106afd9>] lockdep_rcu_dereference+0xaa/0xb3 > >> [<ffffffffa0123a89>] unalias_gfn+0x56/0xab [kvm] > >> [<ffffffffa0119600>] gfn_to_memslot+0x16/0x25 [kvm] > >> [<ffffffffa012ffca>] gfn_to_rmap+0x17/0x6e [kvm] > >> [<ffffffffa01300c1>] rmap_remove+0xa0/0x19d [kvm] > >> [<ffffffffa0130649>] kvm_mmu_zap_page+0x109/0x34d [kvm] > >> [<ffffffffa0130a7e>] kvm_mmu_zap_all+0x35/0x5e [kvm] > >> [<ffffffffa0122870>] kvm_arch_flush_shadow+0x16/0x22 [kvm] > >> [<ffffffffa01189e0>] kvm_mmu_notifier_release+0x15/0x17 [kvm] > >> [<ffffffff810d742c>] __mmu_notifier_release+0x88/0xdf > >> [<ffffffff810d73dc>] ? __mmu_notifier_release+0x38/0xdf > >> [<ffffffff81040848>] ? exit_mm+0xe0/0x115 > >> [<ffffffff810c2cb0>] exit_mmap+0x2c/0x17e > >> [<ffffffff8103c472>] mmput+0x2d/0xd4 > >> [<ffffffff81040870>] exit_mm+0x108/0x115 > >>[...] > >Queued, thank you, Lai! > > Paul, I'd like to merge this via the kvm tree. Very good, I have removed both of these kvm patches. They are yours! ;-) Thanx, Paul -- 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