Re: [PATCH 4/4] KVM: s390: Restore sigset on error path

On Tue, 11 Aug 2026 17:37:38 +0200
Christian Borntraeger <[email protected]> wrote:

> kvm_sigset_activate() installs vcpu->sigset via sigprocmask() and
> stashes the caller's mask in current->real_blocked; only
> kvm_sigset_deactivate() restores it.
> 
> For KVM_RUN on a STOPPED vcpu the error path will not restore the
> userspace mask.  Re-arrange the error handling to also restore the
> signal mask.
> 
> Fixes: 6352e4d2dd9a3 ("KVM: s390: implement KVM_(S|G)ET_MP_STATE for user space state control")
> Cc: [email protected]
> Signed-off-by: Christian Borntraeger <[email protected]>

Reviewed-by: Claudio Imbrenda <[email protected]>

> ---
>  arch/s390/kvm/kvm-s390.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/s390/kvm/kvm-s390.c b/arch/s390/kvm/kvm-s390.c
> index f3814dd60184..608e40401554 100644
> --- a/arch/s390/kvm/kvm-s390.c
> +++ b/arch/s390/kvm/kvm-s390.c
> @@ -5071,7 +5071,7 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>  		pr_err_ratelimited("can't run stopped vcpu %d\n",
>  				   vcpu->vcpu_id);
>  		rc = -EINVAL;
> -		goto out;
> +		goto out_sigset;
>  	}
>  
>  	kernel_fpu_begin(&fpu, KERNEL_FPC | KERNEL_VXR);
> @@ -5101,9 +5101,11 @@ int kvm_arch_vcpu_ioctl_run(struct kvm_vcpu *vcpu)
>  	store_regs(vcpu);
>  	kernel_fpu_end(&fpu, KERNEL_FPC | KERNEL_VXR);
>  
> +	vcpu->stat.exit_userspace++;
> +
> +out_sigset:
>  	kvm_sigset_deactivate(vcpu);
>  
> -	vcpu->stat.exit_userspace++;
>  out:
>  	vcpu_put(vcpu);
>  	return rc;