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Violators will be prosecuted; (version=TLSv1/SSLv3 cipher=AES256-GCM-SHA384 bits=256/256) Thu, 10 Jan 2019 12:58:33 -0000 Received: from d06av21.portsmouth.uk.ibm.com (d06av21.portsmouth.uk.ibm.com [9.149.105.232]) by b06cxnps3074.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id x0ACwWUq61014206 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Thu, 10 Jan 2019 12:58:32 GMT Received: from d06av21.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 5804552050; Thu, 10 Jan 2019 12:58:32 +0000 (GMT) Received: from [9.101.4.34] (unknown [9.101.4.34]) by d06av21.portsmouth.uk.ibm.com (Postfix) with ESMTP id 0C2415204E; Thu, 10 Jan 2019 12:58:32 +0000 (GMT) Subject: Re: [PATCH] powerpc/powernv/npu: Fix oops in pnv_try_setup_npu_table_group() To: Michael Ellerman , Greg Kurz , greg@kroah.com References: <20190109151342.19953-1-fbarrat@linux.ibm.com> <20190109172529.10c45ce6@bahia.lan> <41fc8267-7a40-a3e0-df39-773771b661d2@linux.ibm.com> <20190109175622.75525ff8@bahia.lan> <87h8egsnrs.fsf@concordia.ellerman.id.au> From: Frederic Barrat Date: Thu, 10 Jan 2019 13:58:31 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <87h8egsnrs.fsf@concordia.ellerman.id.au> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 x-cbid: 19011012-0028-0000-0000-000003371560 X-IBM-AV-DETECTION: SAVI=unused REMOTE=unused XFE=unused x-cbparentid: 19011012-0029-0000-0000-000023F42A2E Message-Id: X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-01-10_05:, , signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 priorityscore=1501 malwarescore=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1901100105 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: aik@ozlabs.ru, linuxppc-dev@lists.ozlabs.org, andrew.donnellan@au1.ibm.com, stable@vger.kernel.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Le 10/01/2019 à 13:25, Michael Ellerman a écrit : > Greg Kurz writes: >> On Wed, 9 Jan 2019 17:45:53 +0100 >> Frederic Barrat wrote: >> >>> Le 09/01/2019 à 17:25, Greg Kurz a écrit : >>>> On Wed, 9 Jan 2019 16:13:42 +0100 >>>> Frederic Barrat wrote: >>>> >>>>> With a recent change around IOMMU group, a system with an opencapi >>>>> adapter is no longer booting and we get a kernel oops: >>>>> >>>>> BUG: Kernel NULL pointer dereference at 0x00000028 >>>>> Faulting instruction address: 0xc0000000000aa38c >>>>> Oops: Kernel access of bad area, sig: 7 [#1] >>>>> LE SMP NR_CPUS=2048 NUMA PowerNV >>>>> Modules linked in: >>>>> CPU: 5 PID: 1 Comm: swapper/4 Not tainted 5.0.0-rc1-fxb-00001-g3bd6e94bec12 >>>>> NIP: c0000000000aa38c LR: c0000000000a6608 CTR: c000000000097480 >>>>> REGS: c000000005783700 TRAP: 0300 Not tainted (5.0.0-rc1-fxb-00001-g3bd6 >>>>> MSR: 9000000002009033 CR: 28000228 XER: 20 >>>>> CFAR: c0000000000a6604 DAR: 0000000000000028 DSISR: 00080000 IRQMASK: 0 >>>>> GPR00: c0000000000a6608 c000000005783990 c000000001036100 c0000007bf761860 >>>>> GPR04: 0000000000000000 c000000005783834 0000000000000000 0000000000000000 >>>>> GPR08: 69626d2c6e707500 0000000000000000 0000000000000000 9000000002001003 >>>>> GPR12: 0000000000000000 c0000007bfff8300 c000000000010450 0000000000000000 >>>>> GPR16: c000000000ced938 0000000000000100 c000000000ced948 00000000000a0000 >>>>> GPR20: 00000000000bfffe c000000000ced9a8 0000000000000200 c000000000ced978 >>>>> GPR24: 00000000006080c0 c000000716d09828 c00000002e6fd000 0000000000000000 >>>>> GPR28: c0000007bf4aff68 c0000007bf8d0080 c000000000f23938 c0000007bf761860 >>>>> NIP [c0000000000aa38c] pnv_try_setup_npu_table_group+0x1c/0x1a0 >>>>> LR [c0000000000a6608] pnv_pci_ioda_fixup+0x1f8/0x660 >>>>> Call Trace: >>>>> [c000000005783990] [c0000000000aa3d0] pnv_try_setup_npu_table_group+0x60/0x >>>>> [c0000000057839d0] [c0000000000a661c] pnv_pci_ioda_fixup+0x20c/0x660 >>>>> [c000000005783ab0] [c000000000e1d4c0] pcibios_resource_survey+0x2c8/0x31c >>>>> [c000000005783b90] [c000000000e1caf4] pcibios_init+0xb0/0xe4 >>>>> [c000000005783c10] [c000000000010054] do_one_initcall+0x64/0x264 >>>>> [c000000005783ce0] [c000000000e1132c] kernel_init_freeable+0x36c/0x468 >>>>> [c000000005783db0] [c000000000010474] kernel_init+0x2c/0x148 >>>>> [c000000005783e20] [c00000000000b794] ret_from_kernel_thread+0x5c/0x68 >>>>> >>>>> An opencapi device is using a device PE, so the current code breaks >>>>> because pe->pbus is not defined. >>>>> >>>>> More generally, there's no need to define an IOMMU group for opencapi, >>>>> as the device sends real addresses directly (admittedly, the >>>>> virtualization story is yet to be written). So let's fix it by >>>> >>>> Current plan is to go for mediated VFIO. The real HW stays under the control >>>> of the host ocxl driver, and we still don't need an IOMMU group. >>>> >>>>> skipping the IOMMU group setup for opencapi PHBs. >>>>> >>>>> Fixes: 0bd971676e68 ("powerpc/powernv/npu: Add compound IOMMU groups") >>>>> Signed-off-by: Frederic Barrat >>>>> --- >>>> >>>> Reviewed-by: Greg Kurz >>>> >>>> and >>>> >>>> Cc: stable@vger.kernel.org # v4.20 >>> >>> Thanks for the review! But why did you add stable? that problem is only >>> seen on 5.0-rc1, isn't it? >> >> Based on the fact that 0bd971676e68 was committed in 4.20... but I haven't >> tested :) > > It was committed to a branch based off 4.20-rc2, but it wasn't merged > into the 4.20 release. > > $ git describe --match "v[0-9]*" --contains 0bd971676e68 > v5.0-rc1~137^2~15 > > So it doesn't need to go to stable. Which makes me wonder if Greg (KH) was really talking about that original patch and whether something worthwhile was dropped from stable by mistake? Fred