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From:   linmiaohe <linmiaohe@huawei.com>
To:     <maz@kernel.org>, <pbonzini@redhat.com>, <rkrcmar@redhat.com>,
        <james.morse@arm.com>, <julien.thierry.kdev@gmail.com>,
        <suzuki.poulose@arm.com>, <christoffer.dall@arm.com>,
        <catalin.marinas@arm.com>, <eric.auger@redhat.com>,
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        <andre.przywara@arm.com>, <tglx@linutronix.de>
CC:     <linmiaohe@huawei.com>, <linux-arm-kernel@lists.infradead.org>,
        <kvmarm@lists.cs.columbia.edu>, <linux-kernel@vger.kernel.org>,
        <kvm@vger.kernel.org>
Subject: [PATCH] KVM: vgic: Fix potential double free dist->spis in __kvm_vgic_destroy()
Date:   Thu, 28 Nov 2019 14:38:48 +0800
Message-ID: <1574923128-19956-1-git-send-email-linmiaohe@huawei.com>
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From: Miaohe Lin <linmiaohe@huawei.com>

In kvm_vgic_dist_init() called from kvm_vgic_map_resources(), if
dist->vgic_model is invalid, dist->spis will be freed without set
dist->spis = NULL. And in vgicv2 resources clean up path,
__kvm_vgic_destroy() will be called to free allocated resources.
And dist->spis will be freed again in clean up chain because we
forget to set dist->spis = NULL in kvm_vgic_dist_init() failed
path. So double free would happen.

Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
 virt/kvm/arm/vgic/vgic-init.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/virt/kvm/arm/vgic/vgic-init.c b/virt/kvm/arm/vgic/vgic-init.c
index 53e3969dfb52..c17c29beeb72 100644
--- a/virt/kvm/arm/vgic/vgic-init.c
+++ b/virt/kvm/arm/vgic/vgic-init.c
@@ -171,6 +171,7 @@ static int kvm_vgic_dist_init(struct kvm *kvm, unsigned int nr_spis)
 			break;
 		default:
 			kfree(dist->spis);
+			dist->spis = NULL;
 			return -EINVAL;
 		}
 	}
-- 
2.19.1