linux-kernel - [PATCH v2] KVM: SVM: Fix potential memory leak in svm_cpu

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Message-ID: <1578128209-12891-1-git-send-email-linmiaohe@huawei.com>
Date:   Sat, 4 Jan 2020 16:56:49 +0800
From:   linmiaohe <linmiaohe@...wei.com>
To:     <pbonzini@...hat.com>, <rkrcmar@...hat.com>,
        <sean.j.christopherson@...el.com>, <vkuznets@...hat.com>,
        <wanpengli@...cent.com>, <jmattson@...gle.com>, <joro@...tes.org>,
        <tglx@...utronix.de>, <mingo@...hat.com>, <bp@...en8.de>,
        <hpa@...or.com>
CC:     <linmiaohe@...wei.com>, <kvm@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <x86@...nel.org>,
        <liran.alon@...cle.com>
Subject: [PATCH v2] KVM: SVM: Fix potential memory leak in svm_cpu_init()

From: Miaohe Lin <linmiaohe@...wei.com>

When kmalloc memory for sd->sev_vmcbs failed, we forget to free the page
held by sd->save_area. Also get rid of the var r as '-ENOMEM' is actually
the only possible outcome here.

Reviewed-by: Liran Alon <liran.alon@...cle.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.com>
Signed-off-by: Miaohe Lin <linmiaohe@...wei.com>
---
-v2:
	drop var r as suggested by Vitaly
---
 arch/x86/kvm/svm.c | 13 ++++++-------
 1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 8f1b715dfde8..5f9d6547e0e7 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -1003,33 +1003,32 @@ static void svm_cpu_uninit(int cpu)
 static int svm_cpu_init(int cpu)
 {
 	struct svm_cpu_data *sd;
-	int r;
 
 	sd = kzalloc(sizeof(struct svm_cpu_data), GFP_KERNEL);
 	if (!sd)
 		return -ENOMEM;
 	sd->cpu = cpu;
-	r = -ENOMEM;
 	sd->save_area = alloc_page(GFP_KERNEL);
 	if (!sd->save_area)
-		goto err_1;
+		goto free_cpu_data;
 
 	if (svm_sev_enabled()) {
-		r = -ENOMEM;
 		sd->sev_vmcbs = kmalloc_array(max_sev_asid + 1,
 					      sizeof(void *),
 					      GFP_KERNEL);
 		if (!sd->sev_vmcbs)
-			goto err_1;
+			goto free_save_area;
 	}
 
 	per_cpu(svm_data, cpu) = sd;
 
 	return 0;
 
-err_1:
+free_save_area:
+	__free_page(sd->save_area);
+free_cpu_data:
 	kfree(sd);
-	return r;
+	return -ENOMEM;
 
 }
 
-- 
2.19.1