tree 9dd186153aa405173b6b792843191932244df4c9
parent af2808906aab0bf5786021d45b3ebfca6f4ad72f
author Paolo Bonzini <pbonzini@redhat.com> 1672223621 -0500
committer Paolo Bonzini <pbonzini@redhat.com> 1672224837 -0500

KVM: x86: fix deadlock for KVM_XEN_EVTCHN_RESET

While KVM_XEN_EVTCHN_RESET is usually called with no vCPUs running,
if that happened it could cause a deadlock.  This is due to
kvm_xen_eventfd_reset() doing a synchronize_srcu() inside
a kvm->lock critical section.

To avoid this, first collect all the evtchnfd objects in an
array and free all of them once the kvm->lock critical section
is over and th SRCU grace period has expired.

Reported-by: Michal Luczaj <mhal@rbox.co>
Cc: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>