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authorOliver Upton <oliver.upton@linux.dev>2023-05-30 19:32:13 +0000
committerMarc Zyngier <maz@kernel.org>2023-05-31 08:02:21 +0100
commitf6a27d6dc51b288106adaf053cff9c9b9cc12c4e (patch)
tree3df9b9c30b6c53cfb038014fa6d98b7753230611 /arch
parent811154e234db72f0a11557a84ba9640f8b3bc823 (diff)
KVM: arm64: Drop last page ref in kvm_pgtable_stage2_free_removed()
The reference count on page table allocations is increased for every 'counted' PTE (valid or donated) in the table in addition to the initial reference from ->zalloc_page(). kvm_pgtable_stage2_free_removed() fails to drop the last reference on the root of the table walk, meaning we leak memory. Fix it by dropping the last reference after the free walker returns, at which point all references for 'counted' PTEs have been released. Cc: stable@vger.kernel.org Fixes: 5c359cca1faf ("KVM: arm64: Tear down unlinked stage-2 subtree after break-before-make") Reported-by: Yu Zhao <yuzhao@google.com> Signed-off-by: Oliver Upton <oliver.upton@linux.dev> Tested-by: Yu Zhao <yuzhao@google.com> Signed-off-by: Marc Zyngier <maz@kernel.org> Link: https://lore.kernel.org/r/20230530193213.1663411-1-oliver.upton@linux.dev
Diffstat (limited to 'arch')
-rw-r--r--arch/arm64/kvm/hyp/pgtable.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/arch/arm64/kvm/hyp/pgtable.c b/arch/arm64/kvm/hyp/pgtable.c
index e1eacffbc41f..95dae02ccc2e 100644
--- a/arch/arm64/kvm/hyp/pgtable.c
+++ b/arch/arm64/kvm/hyp/pgtable.c
@@ -1332,4 +1332,7 @@ void kvm_pgtable_stage2_free_removed(struct kvm_pgtable_mm_ops *mm_ops, void *pg
};
WARN_ON(__kvm_pgtable_walk(&data, mm_ops, ptep, level + 1));
+
+ WARN_ON(mm_ops->page_count(pgtable) != 1);
+ mm_ops->put_page(pgtable);
}