[PATCH v3 1/2] KVM: x86/xen: Initialize Xen timer only once
STALE1526d
From: Coleman Dietsch <hidden>
Date: 2022-08-08 19:03:57
Subsystem:
kernel virtual machine for x86 (kvm/x86), kvm x86 xen (kvm/xen), the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Sean Christopherson, Paolo Bonzini, David Woodhouse, Paul Durrant, Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
Revision v3 of 2 in this series.
Revisions (2)
- v2 [diff vs current]
- v3 current
Possibly related (same subject, not in this thread)
- 2022-08-09 · Re: [PATCH v3 1/2] KVM: x86/xen: Initialize Xen timer only once · Paolo Bonzini <pbonzini@redhat.com>
- 2022-08-09 · Re: [PATCH v3 1/2] KVM: x86/xen: Initialize Xen timer only once · Sean Christopherson <seanjc@google.com>
- 2022-08-08 · [PATCH v3 1/2] KVM: x86/xen: Initialize Xen timer only once · Coleman Dietsch <hidden>
Add a check for existing xen timers before initializing a new one.
Currently kvm_xen_init_timer() is called on every
KVM_XEN_VCPU_ATTR_TYPE_TIMER, which is causing the following ODEBUG
crash when vcpu->arch.xen.timer is already set.
ODEBUG: init active (active state 0)
object type: hrtimer hint: xen_timer_callbac0
RIP: 0010:debug_print_object+0x16e/0x250 lib/debugobjects.c:502
Call Trace:
__debug_object_init
debug_hrtimer_init
debug_init
hrtimer_init
kvm_xen_init_timer
kvm_xen_vcpu_set_attr
kvm_arch_vcpu_ioctl
kvm_vcpu_ioctl
vfs_ioctl
Fixes: 536395260582 ("KVM: x86/xen: handle PV timers oneshot mode")
Cc: stable@vger.kernel.org
Link: https://syzkaller.appspot.com/bug?id=8234a9dfd3aafbf092cc5a7cd9842e3ebc45fc42
Reported-by: syzbot+e54f930ed78eb0f85281@syzkaller.appspotmail.com
Signed-off-by: Coleman Dietsch <redacted>
---
arch/x86/kvm/xen.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
index a0c05ccbf4b1..6e554041e862 100644
--- a/arch/x86/kvm/xen.c
+++ b/arch/x86/kvm/xen.c@@ -713,7 +713,9 @@ int kvm_xen_vcpu_set_attr(struct kvm_vcpu *vcpu, struct kvm_xen_vcpu_attr *data) break; } vcpu->arch.xen.timer_virq = data->u.timer.port; - kvm_xen_init_timer(vcpu); + + if (!vcpu->arch.xen.timer.function) + kvm_xen_init_timer(vcpu); /* Restart the timer if it's set */ if (data->u.timer.expires_ns)
--
2.34.1