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Fri, 19 Jun 2026 15:52:01 +0000 (GMT) Received: from p-imbrenda.ibmuc.com (unknown [9.111.54.29]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Fri, 19 Jun 2026 15:52:01 +0000 (GMT) From: Claudio Imbrenda To: linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, borntraeger@de.ibm.com, frankja@linux.ibm.com, david@kernel.org, seiden@linux.ibm.com, nrb@linux.ibm.com, schlameuss@linux.ibm.com, gra@linux.ibm.com, hca@linux.ibm.com, gerald.schaefer@linux.ibm.com, gor@linux.ibm.com, agordeev@linux.ibm.com, svens@linux.ibm.com Subject: [PATCH v4 5/7] KVM: s390: Fix handle_{sske,pfmf} under memory pressure Date: Fri, 19 Jun 2026 17:51:52 +0200 Message-ID: <20260619155154.307572-6-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260619155154.307572-1-imbrenda@linux.ibm.com> References: <20260619155154.307572-1-imbrenda@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Info: AW1haW4tMjYwNjE5MDE1MCBTYWx0ZWRfX19PYrsAm3S8s Oj+sIUuCYLa8x9RJefbaYGK9BJef7JLOiD3L7pUkQs+uocVfiBI4hF71MmZpjZ/WG4vhNn9ZSz4 m1BzH+SMpToz22EknzDCdByZfr/k73w= X-Proofpoint-ORIG-GUID: LTdnDzftNDFH59LL3ZCjtItF_-EE6Vma X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjE5MDE1MCBTYWx0ZWRfXzcQ5rPnWSE34 IEpOkDZvT/Gg9/MKrsVChknJiARWrqWm/IpnEFDNBumuWjtfJJtm0179IwmmX9fj41RUeMstBWU 7cgjvnQOFIpngOGF+QjEH5SFI8Gq7nCyTxmT/aCqC9L97ZTPZ3Pgcn2MiKq8IeBxeRURmuRi0RR EjA/t0KnCWSNmoo9Wl2Zf8smXg5YheN40oBRFJmKIswnXwKX8qaf73suLLMslrbJ2lwwPJOAqrf jJply+NhA5ZYSMQtcY3vYGMnWgU9urlNt47hmb62Lbd/iv80OkeCuuVQBSG+dY08QY220W3hds/ uJisV4noLY8EyV9hmLh1XVpUg33EYoqV3Hx8W3jzQyjcmii+LKQvBriipqBbh1H+rSVTR0Sgy3s w/UTrkP35RfQ/E5U0bHpouvxm+11X0GKUsi+ZiK+DkqIL86PdRopgqLTEyCUw7r9cCRrsBAasWn 6une4cNBHeR3Q5mcZOA== X-Proofpoint-GUID: LTdnDzftNDFH59LL3ZCjtItF_-EE6Vma X-Authority-Analysis: v=2.4 cv=L9gtheT8 c=1 sm=1 tr=0 ts=6a3565a7 cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VnNF1IyMAAAA:8 a=tAqH__8HQhgemv6Xi3YA:9 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1143,Hydra:6.1.125,FMLib:17.12.100.49 definitions=2026-06-19_03,2026-06-18_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 impostorscore=0 malwarescore=0 clxscore=1015 adultscore=0 phishscore=0 lowpriorityscore=0 suspectscore=0 priorityscore=1501 spamscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2606190150 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") Signed-off-by: Claudio Imbrenda --- 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 447ec7ed423d..9bc6fd02ff77 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) -- 2.54.0