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

[Paolo Bonzini]

On 11/06/21 06:59, Wanpeng Li wrote:
> From: Wanpeng Li <wanpengli@xxxxxxxxxxx>
>
> 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@xxxxxxxxxxxxxxx
> Signed-off-by: Wanpeng Li <wanpengli@xxxxxxxxxxx>
> ---
>   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);

Queued, thanks

Paolo