Commit 2fc0f3e2 authored by Will Deacon's avatar Will Deacon Committed by Marc Zyngier
Browse files

KVM: arm64: Don't leave mmu->pgt dangling on kvm_init_stage2_mmu() error 

If kvm_init_stage2_mmu() fails to allocate 'mmu->last_vcpu_ran', it
destroys the newly allocated stage-2 page-table before returning ENOMEM.

Unfortunately, it also leaves a dangling pointer in 'mmu->pgt' which
points at the freed 'kvm_pgtable' structure. This is likely to confuse
the kvm_vcpu_init_nested() failure path which can double-free the
structure if it finds it via kvm_free_stage2_pgd().

Ensure that the dangling 'mmu->pgt' pointer is cleared when returning an
error from kvm_init_stage2_mmu().

Link: https://sashiko.dev/#/patchset/20260327140039.21228-1-will%40kernel.org?patch=12265


Signed-off-by: default avatarWill Deacon <will@kernel.org>
Link: https://patch.msgid.link/20260327192758.21739-2-will@kernel.org


Signed-off-by: default avatarMarc Zyngier <maz@kernel.org>
parent cf6348af

arch/arm64/kvm/mmu.c

+1 −0
Original line number Diff line number Diff line
@@ -1013,6 +1013,7 @@ int kvm_init_stage2_mmu(struct kvm *kvm, struct kvm_s2_mmu *mmu, unsigned long t 


out_destroy_pgtable:

	kvm_stage2_destroy(pgt);

	mmu->pgt = NULL;

out_free_pgtable:

	kfree(pgt);

	return err;