The vcpu_scan_ioapic function in arch/x86/kvm/x86.c in the Linux kernel through 4.19.2 allows local users to cause a denial of service (NULL pointer dereference and BUG) via crafted system calls that reach a situation where ioapic is uninitialized.
www.securityfocus.com/bid/105987
lists.debian.org/debian-lts-announce/2019/03/msg00017.html
lkml.org/lkml/2018/11/20/580
usn.ubuntu.com/3871-1/
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usn.ubuntu.com/3872-1/
usn.ubuntu.com/3878-1/
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usn.ubuntu.com/3879-1/
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