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Wed, 22 Jan 2025 12:44:04 GMT Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id D256120043; Wed, 22 Jan 2025 12:44:03 +0000 (GMT) Received: from smtpav03.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 3D90320040; Wed, 22 Jan 2025 12:43:59 +0000 (GMT) Received: from li-c439904c-24ed-11b2-a85c-b284a6847472.ibm.com.com (unknown [9.43.99.85]) by smtpav03.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 22 Jan 2025 12:43:58 +0000 (GMT) From: Madhavan Srinivasan To: mpe@ellerman.id.au, linuxppc-dev@lists.ozlabs.org, Shivaprasad G Bhat Cc: npiggin@gmail.com, christophe.leroy@csgroup.eu, linux-kernel@vger.kernel.org, vaibhav@linux.ibm.com, vaish123@in.ibm.com, stable@vger.kernel.org Subject: Re: [PATCH] powerpc/pseries/iommu: Don't unset window if it was never set Date: Wed, 22 Jan 2025 18:13:57 +0530 Message-ID: <173754932979.1094869.2005290852678611840.b4-ty@linux.ibm.com> X-Mailer: git-send-email 2.47.0 In-Reply-To: <173674009556.1559.12487885286848752833.stgit@linux.ibm.com> References: <173674009556.1559.12487885286848752833.stgit@linux.ibm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: BL7oZJv0OrjYS4LKyT-JwHw51RSJMHux X-Proofpoint-GUID: 4u0jaRfOtPp97hSgEWWwhOZtnJCnz-LL X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1057,Hydra:6.0.680,FMLib:17.12.68.34 definitions=2025-01-22_05,2025-01-22_02,2024-11-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 adultscore=0 bulkscore=0 mlxlogscore=248 spamscore=0 phishscore=0 mlxscore=0 suspectscore=0 lowpriorityscore=0 priorityscore=1501 clxscore=1011 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.19.0-2411120000 definitions=main-2501220093 On Mon, 13 Jan 2025 03:48:55 +0000, Shivaprasad G Bhat wrote: > On pSeries, when user attempts to use the same vfio container used by > different iommu group, the spapr_tce_set_window() returns -EPERM > and the subsequent cleanup leads to the below crash. > > Kernel attempted to read user page (308) - exploit attempt? > BUG: Kernel NULL pointer dereference on read at 0x00000308 > Faulting instruction address: 0xc0000000001ce358 > Oops: Kernel access of bad area, sig: 11 [#1] > NIP: c0000000001ce358 LR: c0000000001ce05c CTR: c00000000005add0 > > NIP [c0000000001ce358] spapr_tce_unset_window+0x3b8/0x510 > LR [c0000000001ce05c] spapr_tce_unset_window+0xbc/0x510 > Call Trace: > spapr_tce_unset_window+0xbc/0x510 (unreliable) > tce_iommu_attach_group+0x24c/0x340 [vfio_iommu_spapr_tce] > vfio_container_attach_group+0xec/0x240 [vfio] > vfio_group_fops_unl_ioctl+0x548/0xb00 [vfio] > sys_ioctl+0x754/0x1580 > system_call_exception+0x13c/0x330 > system_call_vectored_common+0x15c/0x2ec > > --- interrupt: 3000 > > [...] Applied to powerpc/next. [1/1] powerpc/pseries/iommu: Don't unset window if it was never set https://git.kernel.org/powerpc/c/17391cb2613b82f8c405570fea605af3255ff8d2 Thanks