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authorLai Jiangshan <laijs@cn.fujitsu.com>2010-04-20 14:29:29 +0800
committerAvi Kivity <avi@redhat.com>2010-04-21 11:17:43 +0300
commiteda2beda835697878e309b6049aa0a3bad051590 (patch)
treecb9a07047208a4a266647519a950261fbafba9e5 /virt/kvm/kvm_main.c
parente80e2a60ff7914dae691345a976c80bbbff3ec74 (diff)
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KVM: Add missing srcu_read_lock() for kvm_mmu_notifier_release()
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 [...] Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com> Signed-off-by: Avi Kivity <avi@redhat.com>
Diffstat (limited to 'virt/kvm/kvm_main.c')
-rw-r--r--virt/kvm/kvm_main.c4
1 files changed, 4 insertions, 0 deletions
diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
index 364daacafb5..c82ae249263 100644
--- a/virt/kvm/kvm_main.c
+++ b/virt/kvm/kvm_main.c
@@ -341,7 +341,11 @@ static void kvm_mmu_notifier_release(struct mmu_notifier *mn,
struct mm_struct *mm)
{
struct kvm *kvm = mmu_notifier_to_kvm(mn);
+ int idx;
+
+ idx = srcu_read_lock(&kvm->srcu);
kvm_arch_flush_shadow(kvm);
+ srcu_read_unlock(&kvm->srcu, idx);
}
static const struct mmu_notifier_ops kvm_mmu_notifier_ops = {