diff options
| author | Andy Honig <ahonig@google.com> | 2014-08-27 14:42:54 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2014-11-14 08:47:56 -0800 |
| commit | ca09be78c8d5d2a4fe38ec97a61b3c7fc3463794 (patch) | |
| tree | f42e9907d88f8ee798c6dae1dbc55cdff5ec689c /arch/x86 | |
| parent | 1bea37d63c16c5988d83ac2431c38e0f0a55cf37 (diff) | |
| download | lwn-ca09be78c8d5d2a4fe38ec97a61b3c7fc3463794.tar.gz lwn-ca09be78c8d5d2a4fe38ec97a61b3c7fc3463794.zip | |
KVM: x86: Improve thread safety in pit
commit 2febc839133280d5a5e8e1179c94ea674489dae2 upstream.
There's a race condition in the PIT emulation code in KVM. In
__kvm_migrate_pit_timer the pit_timer object is accessed without
synchronization. If the race condition occurs at the wrong time this
can crash the host kernel.
This fixes CVE-2014-3611.
Signed-off-by: Andrew Honig <ahonig@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kvm/i8254.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/x86/kvm/i8254.c b/arch/x86/kvm/i8254.c index 518d86471b76..298781d4cfb4 100644 --- a/arch/x86/kvm/i8254.c +++ b/arch/x86/kvm/i8254.c @@ -262,8 +262,10 @@ void __kvm_migrate_pit_timer(struct kvm_vcpu *vcpu) return; timer = &pit->pit_state.timer; + mutex_lock(&pit->pit_state.lock); if (hrtimer_cancel(timer)) hrtimer_start_expires(timer, HRTIMER_MODE_ABS); + mutex_unlock(&pit->pit_state.lock); } static void destroy_pit_timer(struct kvm_pit *pit) |