linux-kernel - [PATCH] KVM: X86: Fix x86

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Message-Id: <1623387573-5969-1-git-send-email-wanpengli@tencent.com>
Date:   Thu, 10 Jun 2021 21:59:33 -0700
From:   Wanpeng Li <kernellwp@...il.com>
To:     linux-kernel@...r.kernel.org, kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, stable@...r.kernel.org
Subject: [PATCH] KVM: X86: Fix x86_emulator slab cache leak

From: Wanpeng Li <wanpengli@...cent.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@...r.kernel.org
Signed-off-by: Wanpeng Li <wanpengli@...cent.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