2021-06-11 05:05:30

by Wanpeng Li

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

From: Wanpeng Li <[email protected]>

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: [email protected]
Signed-off-by: Wanpeng Li <[email protected]>
---
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

2021-06-11 15:57:56

by Paolo Bonzini

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

On 11/06/21 06:59, Wanpeng Li wrote:
> From: Wanpeng Li <[email protected]>
>
> 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: [email protected]
> Signed-off-by: Wanpeng Li <[email protected]>
> ---
> 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