In the Linux kernel, the following vulnerability has been resolved:
irqchip/gic-v4: Don't allow a VMOVP on a dying VPE
Kunkun Jiang reported that there is a small window of opportunity for userspace to force a change of affinity for a VPE while the VPE has already been unmapped, but the corresponding doorbell interrupt still visible in /proc/irq/.
Plug the race by checking the value of vmapp_count, which tracks whether the VPE is mapped ot not, and returning an error in this case.
This involves making vmapp_count common to both GICv4.1 and its v4.0 ancestor.
Exploitability
AV:LAC:HPR:LUI:NScope
S:UImpact
C:NI:NA:H4.7/CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H