[PATCH] KVM: X86: Fix x86_emulator slab cache leak

From: Wanpeng Li <kernellwp@gmail.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
	Sean Christopherson <seanjc@google.com>,
	Vitaly Kuznetsov <vkuznets@redhat.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
	stable@vger.kernel.org
Subject: [PATCH] KVM: X86: Fix x86_emulator slab cache leak
Date: Thu, 10 Jun 2021 21:59:33 -0700	[thread overview]
Message-ID: <1623387573-5969-1-git-send-email-wanpengli@tencent.com> (raw)

From: Wanpeng Li <wanpengli@tencent.com>

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>
---
 arch/x86/kvm/x86.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6d3955a6a763..fe26f33e8782 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8258,6 +8258,7 @@ 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);
 #ifdef CONFIG_KVM_XEN
 	static_key_deferred_flush(&kvm_xen_enabled);
-- 
2.25.1

