[PATCH 5.12 136/178] KVM: X86: Fix x86_emulator slab cache leak

Greg Kroah-Hartman
2021-06-21T16:52:34Z

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
@@ -8150,6 +8150,7 @@ 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);