Re: [PATCH] KVM: Fix srcu struct leakage

[Jan Kiszka <jan.kiszka@siemens.com>]

Am 09.11.2010 15:03, Marcelo Tosatti wrote:
> On Tue, Nov 09, 2010 at 02:59:45PM +0100, Jan Kiszka wrote:
>> Am 09.11.2010 14:53, Marcelo Tosatti wrote:
>>> On Tue, Nov 09, 2010 at 12:41:26PM +0100, Jan Kiszka wrote:
>>>> Clean up the srcu struct on vm destruction.
>>>>
>>>> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
>>>> ---
>>>>  virt/kvm/kvm_main.c |    1 +
>>>>  1 files changed, 1 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
>>>> index 4111a4b..6ec58d1 100644
>>>> --- a/virt/kvm/kvm_main.c
>>>> +++ b/virt/kvm/kvm_main.c
>>>> @@ -513,6 +513,7 @@ static void kvm_destroy_vm(struct kvm *kvm)
>>>>  #else
>>>>  	kvm_arch_flush_shadow(kvm);
>>>>  #endif
>>>> +	cleanup_srcu_struct(&kvm->srcu);
>>>>  	kvm_arch_destroy_vm(kvm);
>>>>  	hardware_disable_all();
>>>>  	mmdrop(mm);
>>>> -- 
>>>> 1.7.1
>>>
>>> kvm_arch_destroy_vm does it.
>>
>> Oh, indeed.
>>
>> That I guess it's time to clean up, move generic allocation and release
>> into generic code. Having kvm_arch_create/destroy_vm manage the kvm
>> object allocation does not look very nice (and caused this confusion of
>> mine).
>>
>> Jan
> 
> kvm_iommu_unmap_guest enters SRCU critical section, and "struct kvm" is
> freed at the end of kvm_arch_destroy_vm. Thats why its not in generic
> code.

The problem is the arch-specific allocation of the kvm object on IA64.
All others simply call kmalloc/kzalloc for the struct itself, but IA64
embeds it into some larger context. Not sure why, though.

Jan

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