Re: [PATCH v2 4/4] KVM: PPC: Decrement module refcount if init_vm fails
Nicholas Piggin writes: > Excerpts from Fabiano Rosas's message of January 25, 2022 8:08 am: >> We increment the reference count for KVM-HV/PR before the call to >> kvmppc_core_init_vm. If that function fails we need to decrement the >> refcount. >> >> Signed-off-by: Fabiano Rosas >> --- >> Caught this while testing Nick's LPID patches by looking at >> /sys/module/kvm_hv/refcnt > > Nice catch. Is this the only change in the series? Yes. > You can just use kvm_ops->owner like try_module_get() does I think? Also > try_module_get works on a NULL module same as module_put by the looks, > so you could adjust that in this patch to remove the NULL check so it > is consistent with the put. Sure, I'll send a v3.
Re: [PATCH v2 4/4] KVM: PPC: Decrement module refcount if init_vm fails
Excerpts from Fabiano Rosas's message of January 25, 2022 8:08 am:
> We increment the reference count for KVM-HV/PR before the call to
> kvmppc_core_init_vm. If that function fails we need to decrement the
> refcount.
>
> Signed-off-by: Fabiano Rosas
> ---
> Caught this while testing Nick's LPID patches by looking at
> /sys/module/kvm_hv/refcnt
Nice catch. Is this the only change in the series?
You can just use kvm_ops->owner like try_module_get() does I think? Also
try_module_get works on a NULL module same as module_put by the looks,
so you could adjust that in this patch to remove the NULL check so it
is consistent with the put.
Reviewed-by: Nicholas Piggin
Thanks,
Nick
> ---
> arch/powerpc/kvm/powerpc.c | 7 ++-
> 1 file changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
> index 2ad0ccd202d5..4285d0eac900 100644
> --- a/arch/powerpc/kvm/powerpc.c
> +++ b/arch/powerpc/kvm/powerpc.c
> @@ -431,6 +431,8 @@ int kvm_arch_check_processor_compat(void *opaque)
> int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
> {
> struct kvmppc_ops *kvm_ops = NULL;
> + int r;
> +
> /*
>* if we have both HV and PR enabled, default is HV
>*/
> @@ -456,7 +458,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
> return -ENOENT;
>
> kvm->arch.kvm_ops = kvm_ops;
> - return kvmppc_core_init_vm(kvm);
> + r = kvmppc_core_init_vm(kvm);
> + if (r)
> + module_put(kvm->arch.kvm_ops->owner);
> + return r;
> err_out:
> return -EINVAL;
> }
> --
> 2.34.1
>
>
[PATCH v2 4/4] KVM: PPC: Decrement module refcount if init_vm fails
We increment the reference count for KVM-HV/PR before the call to
kvmppc_core_init_vm. If that function fails we need to decrement the
refcount.
Signed-off-by: Fabiano Rosas
---
Caught this while testing Nick's LPID patches by looking at
/sys/module/kvm_hv/refcnt
---
arch/powerpc/kvm/powerpc.c | 7 ++-
1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
index 2ad0ccd202d5..4285d0eac900 100644
--- a/arch/powerpc/kvm/powerpc.c
+++ b/arch/powerpc/kvm/powerpc.c
@@ -431,6 +431,8 @@ int kvm_arch_check_processor_compat(void *opaque)
int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
{
struct kvmppc_ops *kvm_ops = NULL;
+ int r;
+
/*
* if we have both HV and PR enabled, default is HV
*/
@@ -456,7 +458,10 @@ int kvm_arch_init_vm(struct kvm *kvm, unsigned long type)
return -ENOENT;
kvm->arch.kvm_ops = kvm_ops;
- return kvmppc_core_init_vm(kvm);
+ r = kvmppc_core_init_vm(kvm);
+ if (r)
+ module_put(kvm->arch.kvm_ops->owner);
+ return r;
err_out:
return -EINVAL;
}
--
2.34.1
