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Wed, 12 Aug 2026 13:15:04 +0000 (GMT) Received: from darkmoore (unknown [9.224.78.25]) by smtpav01.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 12 Aug 2026 13:15:04 +0000 (GMT) Precedence: bulk X-Mailing-List: linux-kernel@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 15:14:59 +0200 Message-Id: From: "Christoph Schlameuss" Cc: , , , , , , , , To: "Claudio Imbrenda" , Subject: Re: [PATCH v2 8/9] KVM: s390: Fix potential tiny kernel stack leak X-Mailer: aerc 0.22.0 References: <20260812104436.109741-1-imbrenda@linux.ibm.com> <20260812104436.109741-9-imbrenda@linux.ibm.com> In-Reply-To: <20260812104436.109741-9-imbrenda@linux.ibm.com> X-TM-AS-GCONF: 00 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODEyMDEwNiBTYWx0ZWRfX76GZdeplLsRi 9DmPiDKCivcbbfTC7RRed9XMRFjCA2YTHSKPHfWGJyp7nrw+if4zW1tpj8yrvOVO7wBLbOoUdxb IAQQWpYnbUjwhsqTJrdUjsp27CstKUudDwNLXBUiJu7XI8HO8eRxV5f8Mjrkf2oLTo4qKGnYVN1 e8Y+N6haS1jL477ltemhart+yFJlkzsLmGMP2Q8eCSjQCYF5iEdHLPfNablOqT0j7DG6fYA1133 UmOXXGWWUa/Z1100R7VKR7p3rdZZJq03kekBzJ74PdeOteOfuFHmpjpHNHTPIDmIB2U8m6cUqzK 6u7IOrM/4RE4naYBcCMYLf3xHImwSbnRnpFMGQklziMg/QHy87+BaH6IIbkjkpbZsHDs14SWk5B 0itgWcvabTTR6qdhn0RiCqGYOZuVB2B/GHyno/ckbio1CL7EorF/WqePu6wgxUNcdaTzUHL59Nj 1ilOVB40NdZe0dVDJZg== X-Proofpoint-ORIG-GUID: 3K3fHUwfcibfUwnwfouZwKaJp6feIZa6 X-Proofpoint-Spam-Info: AW1haW4tMjYwODEyMDEwNiBTYWx0ZWRfX6nv78t4k7xsk QrZT3roZdPMaimuMS8/VHRmAdiLe8AnL9b5N1WduhpVIBk1IKNBWtcVV+ukz/7Jvauq+/7kVN2D hLTl9cE8qplRmrZ6ud0e8JdynVWgAVs= X-Authority-Analysis: v=2.4 cv=IfK3n2qa c=1 sm=1 tr=0 ts=6a7c71de cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VnNF1IyMAAAA:8 a=uFAKcTYYjDz6xZQ_b9sA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: 3K3fHUwfcibfUwnwfouZwKaJp6feIZa6 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_03,2026-08-12_01,2025-10-01_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-2608120106 On Wed Aug 12, 2026 at 12:44 PM CEST, Claudio Imbrenda wrote: > In some circumstances, one bit of kernel stack could have been leaked > from dat_cond_set_storage_key(). > > Fix by clearing prev before use. > > Fixes: 8e03e8316eb2 ("KVM: s390: KVM page table management functions: sto= rage keys") > Signed-off-by: Claudio Imbrenda > Reviewed-by: Christian Borntraeger Reviewed-by: Christoph Schlameuss > --- > arch/s390/kvm/dat.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/s390/kvm/dat.c b/arch/s390/kvm/dat.c > index f4dd6f783417..f2ea013cb33e 100644 > --- a/arch/s390/kvm/dat.c > +++ b/arch/s390/kvm/dat.c > @@ -737,6 +737,7 @@ int dat_cond_set_storage_key(struct kvm_s390_mmu_cach= e *mmc, union asce asce, gf > pgste.fp =3D skey.fp; > pgste.gc =3D skey.c; > pgste.gr =3D skey.r; > + prev.skey =3D 0; > =20 > if (!ptep->h.i) { > rc =3D page_cond_set_storage_key(pte_origin(*ptep), skey, &prev, nq, m= r, mc);