Re: #syz test

[syzbot <syzbot+0948c82180d475ad24e2@syzkaller.appspotmail.com>]

> From c3f773691e3c568d67d8628ffd4b7cf25ba8e150 Mon Sep 17 00:00:00 2001
> From: Souradipto Das <souradiptodas6@gmail.com>
> Date: Wed, 20 May 2026 14:11:05 +0530
> Subject: [PATCH] #syz test KVM: x86/xen: Secure gpc refresh_lock mutual
>  exclusion in shared info init
>
> ---
>  arch/x86/kvm/xen.c | 3 +++
>  1 file changed, 3 insertions(+)
>
> diff --git a/arch/x86/kvm/xen.c b/arch/x86/kvm/xen.c
> index 91fd3673c09a..421e4359ce0d 100644
> --- a/arch/x86/kvm/xen.c
> +++ b/arch/x86/kvm/xen.c
> @@ -45,6 +45,8 @@ static int kvm_xen_shared_info_init(struct kvm *kvm)
>  	int ret = 0;
>  	int idx = srcu_read_lock(&kvm->srcu);
>  
> +	mutex_lock(&gpc->refresh_lock);
> +
>  	read_lock_irq(&gpc->lock);
>  	while (!kvm_gpc_check(gpc, PAGE_SIZE)) {
>  		read_unlock_irq(&gpc->lock);
> @@ -101,6 +103,7 @@ static int kvm_xen_shared_info_init(struct kvm *kvm)
>  	kvm_make_all_cpus_request(kvm, KVM_REQ_MASTERCLOCK_UPDATE);
>  
>  out:
> +	mutex_unlock(&gpc->refresh_lock);
>  	srcu_read_unlock(&kvm->srcu, idx);
>  	return ret;
>  }
> -- 
> 2.43.0
>

This crash does not have a reproducer. I cannot test it.