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From:   Jiang Jiasheng <jiasheng@iscas.ac.cn>
To:     pbonzini@redhat.com, seanjc@google.com, vkuznets@redhat.com,
        wanpengli@tencent.com, jmattson@google.com, joro@8bytes.org,
        tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, x86@kernel.org,
        hpa@zytor.com
Cc:     kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
        Jiang Jiasheng <jiasheng@iscas.ac.cn>
Subject: [PATCH 5/5] KVM: SVM: Potentially kvfree the ptr points to error page
Date:   Fri,  3 Sep 2021 09:39:46 +0000
Message-Id: <1630661986-816436-1-git-send-email-jiasheng@iscas.ac.cn>
Precedence: bulk

Directly use the sev_unpin_memory() may cause kvfree()
free the error page, for region->pages may point to the error page.

Signed-off-by: Jiang Jiasheng <jiasheng@iscas.ac.cn>
---
 arch/x86/kvm/svm/sev.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 8d36f0c..ee7d691 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1664,6 +1664,8 @@ find_enc_region(struct kvm *kvm, struct kvm_enc_region *range)
 static void __unregister_enc_region_locked(struct kvm *kvm,
 					   struct enc_region *region)
 {
+	if (IS_ERR(region->pages))
+		return;
 	sev_unpin_memory(kvm, region->pages, region->npages);
 	list_del(&region->list);
 	kfree(region);
-- 
2.7.4