The routine controlling the setup of dirty video RAM tracking latches
the value of a pointer before taking the respective guarding lock, thus
making it possible for a stale pointer to be used by the time the lock
got acquired and the pointer gets dereferenced.
Malicious or buggy stub domain kernels or tool stacks otherwise living
outside of Domain0 can mount a denial of service attack which, if
successful, can affect the whole system.
Only domains controlling HVM guests can exploit this vulnerability.
(This includes domains providing hardware emulation services to HVM
Red Hat would like to thank the Xen for reporting this issue.
This issue did not affect the versions of the kernel-xen package as shipped with Red Hat Enterprise Linux 5.
Created xen tracking bugs for this issue:
Affects: fedora-all [bug 1145736]