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Tue, 18 Aug 2026 20:16:15 +0000 (GMT) Received: from [9.61.131.241] (unknown [9.61.131.241]) by smtpav02.dal12v.mail.ibm.com (Postfix) with ESMTP; Tue, 18 Aug 2026 20:16:15 +0000 (GMT) Message-ID: <98713094-10c0-47fa-b54c-c67ab82f7a51@linux.ibm.com> Date: Tue, 18 Aug 2026 16:16:15 -0400 Precedence: bulk X-Mailing-List: linux-s390@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] iommu/s390: Fix NULL dereference in iova_to_phys() with ZPCI_TABLE_TYPE_RFX To: Niklas Schnelle , Farhan Ali , Omar Elghoul , Gerd Bayer , Benjamin Block , Julian Ruess , "Joerg Roedel (AMD)" , Will Deacon , Robin Murphy , Joerg Roedel Cc: Heiko Carstens , Vasily Gorbik , Alexander Gordeev , Sven Schnelle , Ramesh Errabolu , Tobias Schumacher , Halil Pasic , Peter Oberparleiter , Gerald Schaefer , Christian Borntraeger , linux-s390@vger.kernel.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org References: <20260818-iommu_fix_iova_to_phys-v1-1-1cd76d2a55b8@linux.ibm.com> Content-Language: en-US From: Matthew Rosato In-Reply-To: <20260818-iommu_fix_iova_to_phys-v1-1-1cd76d2a55b8@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: RiMDqjaebPd6v69bqhv844lhZhQfWhgC X-Authority-Analysis: v=2.4 cv=NLLlPU6g c=1 sm=1 tr=0 ts=6a84bd93 cx=c_pps a=5BHTudwdYE3Te8bg5FgnPg==:117 a=5BHTudwdYE3Te8bg5FgnPg==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=th3aBrcy0Tt1vy9RbOYA:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Info: AW1haW4tMjYwODE4MDE0NyBTYWx0ZWRfX46rrz4NFBge2 1Gi25W6pprn6qgypQ3CyZk/C07s/juEqBaJU0uAs4TWZndURfYbs1VW6/O6/V+iJIXqWHczWjdf t0XDNpUWYo7oqh/+GytdKPiiQrbB4iU= X-Proofpoint-ORIG-GUID: RiMDqjaebPd6v69bqhv844lhZhQfWhgC X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODE4MDE0NyBTYWx0ZWRfX/hAb4AoPEJJ8 2hJpeKbfgMIO+3Ay4Wdwl/fZa+VYtnHAOOG9xv0AtoB0EYyeyYsXleSDaapj1yOgZYVumi2EKfH xftmsOXOo8uBQcVjb84T4XQRG74WdXjg8k8L0yC0YvDEQ/64w+jJ2vXfjjy96Cbg2VncmTYlWaQ MPNt9o4lVwJCSH9amr0wa19yH04Czu8FUYcJyeB8c5+JZH5hME4NAb9HmTkldUL6cE5BF+9Wykq yRkHF2j/yI1Bx1YdaVm7M1w+GvDJYa7Wb/RqGT1uLa2KcwHwOWKHQyjDuuKxBjbKXhijJYdb+nr HxV6wqA7MYDOe+5ZcYo+03P1rXji7KR2J7v1EzvhXIe9SyTZKM23I0VBwBo9H5/oSL2SCJ1pamp HS+SLaqruArRebk9V1DqiuHLWT3EpTc37RhyxpwuG7UywfNQITy2fMDjDm/eLRZdmKdZliwA/t6 lIrSCnePET8vqvREtBg== 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=2026-08-18_04,2026-08-18_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 spamscore=0 lowpriorityscore=0 phishscore=0 impostorscore=0 malwarescore=0 suspectscore=0 clxscore=1011 adultscore=0 priorityscore=1501 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608180147 On 8/18/26 3:13 PM, Niklas Schnelle wrote: > When using a 5-level translation table via ZPCI_TABLE_TYPE_RFX > get_rso_from_iova() returns NULL when the region-first entry is invalid. > Yet in get_rto_from_iova() the region-second origin rso is not checked > to be non-NULL before accessing rso[rsx] leading to a NULL pointer > dereference instead of a NULL return when iova_to_phys() is called on > a unmapped IOVA. Fix this by adding the missing NULL check. > > Cc: stable@vger.kernel.org > Fixes: 81244074b518 ("iommu/s390: allow larger region tables") > Signed-off-by: Niklas Schnelle Reviewed-by: Matthew Rosato > --- > drivers/iommu/s390-iommu.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/iommu/s390-iommu.c b/drivers/iommu/s390-iommu.c > index f148f559ac56..58ca7727b7f2 100644 > --- a/drivers/iommu/s390-iommu.c > +++ b/drivers/iommu/s390-iommu.c > @@ -974,6 +974,8 @@ static unsigned long *get_rto_from_iova(struct s390_domain *domain, > case ZPCI_TABLE_TYPE_RFX: > case ZPCI_TABLE_TYPE_RSX: > rso = get_rso_from_iova(domain, iova); > + if (!rso) > + return NULL; > rsx = calc_rsx(iova); > rse = READ_ONCE(rso[rsx]); > if (!reg_entry_isvalid(rse)) > > --- > base-commit: 8d3ae59288f1e7d58d76558a6ee96d533bc5019f > change-id: 20260818-iommu_fix_iova_to_phys-5879275b95ec > > Best regards,