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Wed, 12 Aug 2026 08:06:08 +0000 (GMT) Received: from darkmoore (unknown [9.224.78.25]) by smtpav02.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 12 Aug 2026 08:06:08 +0000 (GMT) Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Wed, 12 Aug 2026 10:06:03 +0200 Message-Id: From: "Christoph Schlameuss" Cc: , , , , , , , , To: "Claudio Imbrenda" , Subject: Re: [PATCH v1 01/11] KVM: s390: Properly handle NULL pointer in dat_cond_set_storage_key() X-Mailer: aerc 0.22.0 References: <20260811155641.219777-1-imbrenda@linux.ibm.com> <20260811155641.219777-2-imbrenda@linux.ibm.com> In-Reply-To: <20260811155641.219777-2-imbrenda@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODEyMDA2MyBTYWx0ZWRfX9hCYABSFxvSz lMFh6HHrYujeXHlgd5NSCusb1jMvvO2ONH1SptzFOHcMxQafM0SwLJpcT4Y1ZIuf2WnWM1Ro/jM VimbhaTYZxIR2NzMn9pIanm8HaEVKgbcnQJIErHrCQ6wnFy0F9owf2v2+wqyFgE4mjU9Kr/cVd2 66cqBjHJM/T+Jkiw8jkYDwAs07QRlCBrPSddkB3MgSjlbUPQmhV7NECHXk4az7bsWNr6q/Kt3GK WQ1+ICYWCMWFxB5abm+D9lEEAKOLbKwYkzNLNjahvrGgBRvIn3nAO6KjObnetEqhUNUPM7Xudcj EvYePH1aMIkeKCse6/tU9xVlG5gUPHrLS9ykKZqbIIb2BI5opEgLaPAJIzBTtveKufVUJb4NJgl W9j+F+qshSXtNQmj50F6b0WDXfiMn4UFMyPURm5BJX7O34TcnPxS2Jr0ibsbcYUABdRdIlKoiIt Y/gDw8gSl2gxCw2q60g== X-Proofpoint-ORIG-GUID: z0XiUNlLlQicHzHKg3Qs5Vck4vnDwsHr X-Proofpoint-Spam-Info: AW1haW4tMjYwODEyMDA2MyBTYWx0ZWRfX9V9HxvvluIzj GXJh++N/CiOSJL+//096LR2vKmo1oriOgGd0BxBH54uV8TyBi4yi9f4INjtBFQb30badfFTglhS H+dMjso+bYiJYqQFNTuwmPrKKr6be/0= X-Authority-Analysis: v=2.4 cv=IfK3n2qa c=1 sm=1 tr=0 ts=6a7c2975 cx=c_pps a=AfN7/Ok6k8XGzOShvHwTGQ==:117 a=AfN7/Ok6k8XGzOShvHwTGQ==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VnNF1IyMAAAA:8 a=bgBGiGX_jkhGwFKEUkAA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: z0XiUNlLlQicHzHKg3Qs5Vck4vnDwsHr 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_02,2026-08-10_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 priorityscore=1501 impostorscore=0 bulkscore=0 clxscore=1015 lowpriorityscore=0 adultscore=0 malwarescore=0 spamscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608120063 On Tue Aug 11, 2026 at 5:56 PM CEST, Claudio Imbrenda wrote: > 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: sto= rage keys") > Signed-off-by: Claudio Imbrenda Reviewed-by: Christoph Schlameuss > --- > 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_cac= he *mmc, union asce asce, gf > if (rc) > return rc; > =20 > - if (!ptep) > + if (!ptep) { > + if (!oldkey) > + oldkey =3D &prev; > return page_cond_set_storage_key(large_crste_to_phys(*crstep, gfn), sk= ey, oldkey, > nq, mr, mc); > + } > =20 > old =3D pgste_get_lock(ptep); > pgste =3D old;