From 2bd74dce0814acc382cfd6903ec902fdcd7b0fed Mon Sep 17 00:00:00 2001 From: Claudio Imbrenda Date: Tue, 23 Jun 2026 17:33:26 +0200 Subject: [PATCH] KVM: s390: Fix handle_{sske,pfmf} under memory pressure Under heavy memory pressure, handle_sske() and handle_pfmf() might cause an endless loop if the mmu cache runs empty, the atomic allocations fail, and the top-up function also fails. While quite unlikely, that scenario is not impossible. Fix the issue by not ignoring the return value of kvm_s390_mmu_cache_topup(), and appropriately returning an error code in case of failure. Fixes: e38c884df921 ("KVM: s390: Switch to new gmap") Reviewed-by: Christian Borntraeger Signed-off-by: Claudio Imbrenda Message-ID: <20260623153331.233784-6-imbrenda@linux.ibm.com> --- arch/s390/kvm/priv.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/arch/s390/kvm/priv.c b/arch/s390/kvm/priv.c index 447ec7ed423dc..9bc6fd02ff777 100644 --- a/arch/s390/kvm/priv.c +++ b/arch/s390/kvm/priv.c @@ -366,7 +366,9 @@ static int handle_sske(struct kvm_vcpu *vcpu) if (rc > 1) return kvm_s390_inject_program_int(vcpu, PGM_ADDRESSING); if (rc == -ENOMEM) { - kvm_s390_mmu_cache_topup(vcpu->arch.mc); + rc = kvm_s390_mmu_cache_topup(vcpu->arch.mc); + if (rc) + return rc; continue; } if (rc < 0) @@ -1122,7 +1124,9 @@ static int handle_pfmf(struct kvm_vcpu *vcpu) if (rc > 1) return kvm_s390_inject_program_int(vcpu, rc); if (rc == -ENOMEM) { - kvm_s390_mmu_cache_topup(vcpu->arch.mc); + rc = kvm_s390_mmu_cache_topup(vcpu->arch.mc); + if (rc) + return rc; continue; } if (rc < 0) -- 2.47.3