Re: [PATCH 1/3] KVM: s390: remove user triggerable WARN_ON

[Matthew Rosato <mjrosato@linux.ibm.com>]

On 8/4/26 8:06 AM, Christian Borntraeger wrote:
> pin_map_page() fails legitimately whenever the userspace mapping behind
> the adapter route has gone away, e.g. when the VMM unmaps that memory.
> As this can happen without a kernel programming error, remove the
> WARN_ON.
> 
> Fixes: 8c0141b7c13c ("KVM: s390: Enable adapter_indicators_set to use mapped pages")
> Cc: Douglas Freimuth <freimuth@linux.ibm.com>
> Cc: Matthew Rosato <mjrosato@linux.ibm.com>
> Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>

Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>

> ---
>  arch/s390/kvm/interrupt.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/s390/kvm/interrupt.c b/arch/s390/kvm/interrupt.c
> index 8f24bcd1a6d3..23f0e0821474 100644
> --- a/arch/s390/kvm/interrupt.c
> +++ b/arch/s390/kvm/interrupt.c
> @@ -3013,7 +3013,7 @@ static int adapter_indicators_set(struct kvm *kvm,
>  	if (!summary_info) {
>  		spin_unlock_irqrestore(&adapter->maps_lock, flags);
>  		summary_page = pin_map_page(kvm, adapter_int->summary_addr, 0);
> -		if (WARN_ON_ONCE(!summary_page))
> +		if (!summary_page)
>  			return -1;
>  		idx = srcu_read_lock(&kvm->srcu);
>  		map = page_address(summary_page);