The p2m_pod_emergency_sweep function in arch/x86/mm/p2m-pod.c in Xen 3.4.x, 3.5.x, and 3.6.x is not preemptible, which allows local x86 HVM guest administrators to cause a denial of service (CPU consumption and possibly reboot) via crafted memory contents that triggers a "time-consuming linear scan," related to Populate-on-Demand.
The MITRE CVE dictionary describes this issue as:
Find out more about CVE-2015-7970 from the MITRE CVE dictionary dictionary and NIST NVD.
| Platform | Package | State |
|---|---|---|
| Red Hat Enterprise Linux 5 | xen | Not affected |
Running only PV guests will avoid this issue. Running HVM guest without enabling Populate-on-Demand mode (so, ensuring that maxmem==memory) will avoid this issue.
Vulmon