[PATCH v2 5/7] KVM: s390: ucontrol: Add missing locking around gmap_remove_child()

[Claudio Imbrenda]

gmap_remove_child() needs to be called while holding the children_lock
of the parent gmap. This was not the case in the error handling path of
kvm_arch_vcpu_create() for UCONTROL guests.

Fix by adding the missing lock.

Fixes: e38c884df921 ("KVM: s390: Switch to new gmap")
Signed-off-by: Claudio Imbrenda <imbrenda@xxxxxxxxxxxxx>
---
 arch/s390/kvm/kvm-s390.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
index 5c2408fc5a8c..fc0a884d7f54 100644
--- a/arch/s390/kvm/kvm-s390.c
+++ b/arch/s390/kvm/kvm-s390.c
@@ -3866,7 +3866,8 @@ int kvm_arch_vcpu_create(struct kvm_vcpu *vcpu)
 
 out_ucontrol_uninit:
 	if (kvm_is_ucontrol(vcpu->kvm)) {
-		gmap_remove_child(vcpu->arch.gmap);
+		scoped_guard(spinlock, &vcpu->kvm->arch.gmap->children_lock)
+			gmap_remove_child(vcpu->arch.gmap);
 		vcpu->arch.gmap = gmap_put(vcpu->arch.gmap);
 	}
 out_free_sie_block:
-- 
2.55.0