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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Wanpeng Li <wanpengli@tencent.com>,
        Paolo Bonzini <pbonzini@redhat.com>
Subject: [PATCH 5.10 114/146] KVM: X86: Fix x86_emulator slab cache leak
Date:   Mon, 21 Jun 2021 18:15:44 +0200
Message-Id: <20210621154918.625077118@linuxfoundation.org>
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From: Wanpeng Li <wanpengli@tencent.com>

commit dfdc0a714d241bfbf951886c373cd1ae463fcc25 upstream.

Commit c9b8b07cded58 (KVM: x86: Dynamically allocate per-vCPU emulation context)
tries to allocate per-vCPU emulation context dynamically, however, the
x86_emulator slab cache is still exiting after the kvm module is unload
as below after destroying the VM and unloading the kvm module.

grep x86_emulator /proc/slabinfo
x86_emulator          36     36   2672   12    8 : tunables    0    0    0 : slabdata      3      3      0

This patch fixes this slab cache leak by destroying the x86_emulator slab cache
when the kvm module is unloaded.

Fixes: c9b8b07cded58 (KVM: x86: Dynamically allocate per-vCPU emulation context)
Cc: stable@vger.kernel.org
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
Message-Id: <1623387573-5969-1-git-send-email-wanpengli@tencent.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 arch/x86/kvm/x86.c |    1 +
 1 file changed, 1 insertion(+)

--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8021,6 +8021,7 @@ void kvm_arch_exit(void)
 	kvm_x86_ops.hardware_enable = NULL;
 	kvm_mmu_module_exit();
 	free_percpu(user_return_msrs);
+	kmem_cache_destroy(x86_emulator_cache);
 	kmem_cache_destroy(x86_fpu_cache);
 }