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authorSteve Rutherford2020-04-16 12:11:52 -0700
committerPaolo Bonzini2020-04-17 11:04:01 -0400
commit7289fdb5dcdbc5155b5531529c44105868a762f2 (patch)
tree3c8061ee42878e133b11a298ed7e53afc8a2c53c /arch
parent56a87e5d997b722acf2a5dd5c938d574d8c95da6 (diff)
KVM: Remove CREATE_IRQCHIP/SET_PIT2 race
Fixes a NULL pointer dereference, caused by the PIT firing an interrupt before the interrupt table has been initialized. SET_PIT2 can race with the creation of the IRQchip. In particular, if SET_PIT2 is called with a low PIT timer period (after the creation of the IOAPIC, but before the instantiation of the irq routes), the PIT can fire an interrupt at an uninitialized table. Signed-off-by: Steve Rutherford <srutherford@google.com> Signed-off-by: Jon Cargille <jcargill@google.com> Reviewed-by: Jim Mattson <jmattson@google.com> Message-Id: <20200416191152.259434-1-jcargill@google.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kvm/x86.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 027dfd278a97..3cc3f673785c 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5049,10 +5049,13 @@ set_identity_unlock:
r = -EFAULT;
if (copy_from_user(&u.ps, argp, sizeof(u.ps)))
goto out;
+ mutex_lock(&kvm->lock);
r = -ENXIO;
if (!kvm->arch.vpit)
- goto out;
+ goto set_pit_out;
r = kvm_vm_ioctl_set_pit(kvm, &u.ps);
+set_pit_out:
+ mutex_unlock(&kvm->lock);
break;
}
case KVM_GET_PIT2: {
@@ -5072,10 +5075,13 @@ set_identity_unlock:
r = -EFAULT;
if (copy_from_user(&u.ps2, argp, sizeof(u.ps2)))
goto out;
+ mutex_lock(&kvm->lock);
r = -ENXIO;
if (!kvm->arch.vpit)
- goto out;
+ goto set_pit2_out;
r = kvm_vm_ioctl_set_pit2(kvm, &u.ps2);
+set_pit2_out:
+ mutex_unlock(&kvm->lock);
break;
}
case KVM_REINJECT_CONTROL: {