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Mon, 22 Jun 2026 11:44:05 +0000 (GMT) Received: from [9.224.77.173] (unknown [9.224.77.173]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Mon, 22 Jun 2026 11:44:05 +0000 (GMT) Message-ID: <81a58478-6a39-4bdf-84a0-5da4d29b6407@de.ibm.com> Date: Mon, 22 Jun 2026 13:44:05 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 5/7] KVM: s390: Fix handle_{sske,pfmf} under memory pressure To: Claudio Imbrenda , linux-kernel@vger.kernel.org Cc: kvm@vger.kernel.org, linux-s390@vger.kernel.org, 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 References: <20260619155154.307572-1-imbrenda@linux.ibm.com> <20260619155154.307572-6-imbrenda@linux.ibm.com> Content-Language: en-US From: Christian Borntraeger In-Reply-To: <20260619155154.307572-6-imbrenda@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: aOTrwq3OLybzbqoDIx9AEz7FtJfv2KAF X-Proofpoint-Spam-Info: AW1haW4tMjYwNjIyMDExMiBTYWx0ZWRfXy4ZARlW6+85r wiDexrlGK7z3zKOnffTenw3OEPCZB/vEYNxi2uC3IwYRU8R1Ztp4zhLwKYftK+pP6EtzPOaRHbg G4UX+7U5uwaoLRKz9KyBqyb1u/wcujc= X-Authority-Analysis: v=2.4 cv=c62bhx9l c=1 sm=1 tr=0 ts=6a39200a cx=c_pps a=aDMHemPKRhS1OARIsFnwRA==:117 a=aDMHemPKRhS1OARIsFnwRA==:17 a=IkcTkHD0fZMA:10 a=FelO9ux0wxsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=V8glGbnc2Ofi9Qvn3v5h:22 a=VnNF1IyMAAAA:8 a=eumESayLdrPmyjtxqS8A:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwNjIyMDExMiBTYWx0ZWRfX5xerWm36llp/ KqlY5F19TqA75hhUYN7UhR+bY2zizs8sWz84+8M1jt1YQnPScAOTyHFfINb6dBvXgW6S8fJ4e9t y60+XCUs0//h6807Pd30aFYGNVtHiE98Yx8NrPU7usHG54xCgdt7wH3X5PvMDvWeEs6anlVE+Vg qlO9wXHK+1abc0cRb9SFpyGd1pXoE6LktiPvx4GJjlqk7EUl/Q6e/t5I9G5qtp0a0jFJPGspIpg 0tpxUUfpnNYFQkXkULzY9tEe2YRDwX7FU9D+tTu68hj0EJHBbADj/Edaf7+YecbSLy4DD620Sxh 3yxzITiww/EdfldE5+Ypu7eLRSyBi2ZU/yNbvprGUk+Dl/rsF3UByrhzE1vk8m2yJx4Tp1P/nSa UpmdoSeOkShpKU9+HJohC3tyl5UgKGjysenhq8bqQMDoIdl1RcRNn9/cEW7Hy5Fdc7u3Pyc2oAF Y/jVG0DJRp3STYI4NLA== X-Proofpoint-ORIG-GUID: aOTrwq3OLybzbqoDIx9AEz7FtJfv2KAF 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_02,2026-06-18_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 impostorscore=0 adultscore=0 clxscore=1015 suspectscore=0 priorityscore=1501 phishscore=0 spamscore=0 bulkscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2606220112 Am 19.06.26 um 17:51 schrieb Claudio Imbrenda: > 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)