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Mon, 22 Jun 2026 16:07:41 +0000 (GMT) Received: from p-imbrenda.ehn-de.ibm.com (unknown [9.224.75.30]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 22 Jun 2026 16:07:41 +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 v5 5/9] KVM: s390: Fix handle_{sske,pfmf} under memory pressure Date: Mon, 22 Jun 2026 18:07:35 +0200 Message-ID: <20260622160739.202044-6-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.54.0 In-Reply-To: <20260622160739.202044-1-imbrenda@linux.ibm.com> References: <20260622160739.202044-1-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-Authority-Analysis: v=2.4 cv=I4VVgtgg c=1 sm=1 tr=0 ts=6a395dd2 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=uAbxVGIbfxUO_5tXvNgY:22 a=VnNF1IyMAAAA:8 a=tAqH__8HQhgemv6Xi3YA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjIyMDE1NyBTYWx0ZWRfX4nGy4CADBj4K g/MKAknO67NOvBRRroWsZsA5hq0An9vpUDjIElemsWiuuJcKo3yDWAsdnLYA9ybiIc7phFwYGw6 yIBqrmfW3gfNM7bIH46/+IdHVwivQgxNNryTHg8OX32zmnJWzZsXxJeQxHNZaQKYNqum4JB0UJs 0T4nUpin5ptmIJK7zaaGUP1EJT+huoDpn39NYO0gpjaKMaB2yc/rzrV3zmt5XTCM9a7JaGCRY9Y tDAgq0JEMrzo+NjVEQPLJg2f7k+Ejrczfw/mplcymM7a9bVHaGnH7ggc8Zu9f7ij/f58m+P4zv0 P6gR6k24GqKgXcQx/FrLgacTpYQrzzptlZY/uIHHWdSzaNvuDGoAm2kelAjGW2u+2ziWhByrShy 1ettGyYUjgcJRGsgRo3m//K42xDfS8CYtwMGQP4rhNUyievUKwMoO9aeKWYm2NnMCfDVvIb17sH n3LwuuLeFSmD2XawhDw== X-Proofpoint-GUID: 1eLRfbO8NMGxxgH8C-zTjWFNJSefLaLy X-Proofpoint-ORIG-GUID: 1eLRfbO8NMGxxgH8C-zTjWFNJSefLaLy X-Proofpoint-Spam-Info: AW1haW4tMjYwNjIyMDE1NyBTYWx0ZWRfX8SN6h6bWWzmx vzQoEqWlz2h7JW2/OOcHHqjA3u0qhPzPVENSwnDh2d1L+Jm8qfl/ugWu9UBr6guKWY94D8XSiB8 S9AS4cQZhWCCkFDoM4cSsd9a/BX2FOs= 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=2026-06-22_03,2026-06-22_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 malwarescore=0 clxscore=1015 impostorscore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 priorityscore=1501 adultscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2606220157 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 Reviewed-by: Christian Borntraeger --- 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