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Wed, 12 Aug 2026 10:44:37 +0000 (GMT) Received: from p-imbrenda.ehn-de.ibm.com (unknown [9.224.75.30]) by smtpav04.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 12 Aug 2026 10:44:37 +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 Subject: [PATCH v2 1/9] KVM: s390: Properly handle NULL pointer in dat_cond_set_storage_key() Date: Wed, 12 Aug 2026 12:44:28 +0200 Message-ID: <20260812104436.109741-2-imbrenda@linux.ibm.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260812104436.109741-1-imbrenda@linux.ibm.com> References: <20260812104436.109741-1-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-GUID: aXwSQ_WH9gigVBIa_yJVr5tyjpSuW_4Z X-Authority-Analysis: v=2.4 cv=PbDPQChd c=1 sm=1 tr=0 ts=6a7c4e9b cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=iQ6ETzBq9ecOQQE5vZCe:22 a=VnNF1IyMAAAA:8 a=HXcwjgiTS1qyJsQYY4QA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODEyMDA4NCBTYWx0ZWRfX3PwocYy8oT0r 1Ir0ib83Zphw5LH7+9misZ4wK2+1bJ5/bnuMaYVa5VJbJF36KotQABpO23fGFPJe9iBVPiBs7VK 999ITnQSqk/NpJAD0ooPovbrInm/fRRLQ/X3yrBnJU/nK6uwVFQgs6xmZw4Kn4EBQUM33PTo8UD R4Mqd12PNlBGqPn+g1VXFLEGPxGvz18WVinHBWocDO3two03oq7zUck1Sm9mL2/NNBh3a+YfdCr JiiqNnuRArPijR2DyWUShO+/2L4NAabMbBpohVwz8YqpLQBQP/jVe5RfUsMZwEEcMlFyosR32WN W0bYpUrNOEGd31/aeX9jdu4yoENw9fOPBtn+EdPpt0I1xg1HEUKG31uiUMBeInW407FFxOMRs82 HctHp12bzVDK0hrD8h+x+UnpKkk7XetwsJya9Gf+jPNeV/99cAlVh850htyHxzwPyRaeyMUgJnA kvt218WA3lXVL1tYFEg== X-Proofpoint-ORIG-GUID: aXwSQ_WH9gigVBIa_yJVr5tyjpSuW_4Z X-Proofpoint-Spam-Info: AW1haW4tMjYwODEyMDA4NCBTYWx0ZWRfX7bjoyciM3d6u fhIhMjYEdbyF71EfPHHFTipgiA6cGTCv8OYAdfeHluoqvQUeTd6Qx4DMYw2atRL6kt87/UoOTlz R+9ouyugcg+sVcgUyU97JkUyKnVNKc4= X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-12_03,2026-08-10_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 bulkscore=0 impostorscore=0 malwarescore=0 adultscore=0 clxscore=1015 priorityscore=1501 suspectscore=0 phishscore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608120084 Some callers pass NULL as oldkey. Calling page_cond_set_storage_key() will cause that NULL pointer to get dereferenced. Fix by checking for NULL and assigning the pointer to a dummy local variable to avoid crashes. Fixes: 8e03e8316eb2 ("KVM: s390: KVM page table management functions: storage keys") Signed-off-by: Claudio Imbrenda Reviewed-by: Christian Borntraeger --- arch/s390/kvm/dat.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/arch/s390/kvm/dat.c b/arch/s390/kvm/dat.c index 3f2d6e8902d7..165c704fcf29 100644 --- a/arch/s390/kvm/dat.c +++ b/arch/s390/kvm/dat.c @@ -722,9 +722,12 @@ int dat_cond_set_storage_key(struct kvm_s390_mmu_cache *mmc, union asce asce, gf if (rc) return rc; - if (!ptep) + if (!ptep) { + if (!oldkey) + oldkey = &prev; return page_cond_set_storage_key(large_crste_to_phys(*crstep, gfn), skey, oldkey, nq, mr, mc); + } old = pgste_get_lock(ptep); pgste = old; -- 2.55.0