Bug 2373504 (CVE-2022-50227)

Summary: CVE-2022-50227 kernel: KVM: x86/xen: Initialize Xen timer only once
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: dfreiber, drow, jburrell, vkumar
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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Description OSIDB Bzimport 2025-06-18 12:05:54 UTC 
In the Linux kernel, the following vulnerability has been resolved:

KVM: x86/xen: Initialize Xen timer only once

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
Comment 1 Avinash Hanwate 2025-06-19 21:07:07 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2025061849-CVE-2022-50227-890e@gregkh/T