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Tue, 11 Aug 2026 04:23:09 +0000 (GMT) Received: from smtpav04.dal12v.mail.ibm.com (smtpav04.dal12v.mail.ibm.com [10.241.53.103]) by smtprelay01.wdc07v.mail.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 67B4N7sT6161202 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Tue, 11 Aug 2026 04:23:07 GMT Received: from smtpav04.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 4C28258052; Tue, 11 Aug 2026 04:23:07 +0000 (GMT) Received: from smtpav04.dal12v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C6B6E5805E; Tue, 11 Aug 2026 04:23:04 +0000 (GMT) Received: from [9.123.12.38] (unknown [9.123.12.38]) by smtpav04.dal12v.mail.ibm.com (Postfix) with ESMTP; Tue, 11 Aug 2026 04:23:04 +0000 (GMT) Message-ID: <627c5c2f-a0b3-4fba-811f-7b4ed4c74dbb@linux.ibm.com> Date: Tue, 11 Aug 2026 09:53:03 +0530 X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [BUG] powerpc: userspace processes crash in ld64.so.2 when running recent linux-next kernels Content-Language: en-GB From: Venkat Rao Bagalkote To: Madhavan Srinivasan , Christophe Leroy , Ritesh Harjani , linuxppc-dev , ajd@linux.ibm.com Cc: LKML , Christian Brauner , "linux-mm@kvack.org" References: <75419f88-eab9-444b-bf97-28a9765819ad@linux.ibm.com> In-Reply-To: <75419f88-eab9-444b-bf97-28a9765819ad@linux.ibm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Authority-Analysis: v=2.4 cv=AMtp2X5w c=1 sm=1 tr=0 ts=6a7aa3ae 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=Y2IxJ9c9Rs8Kov3niI8_:22 a=VnNF1IyMAAAA:8 a=ooee5C11TIdXIoiR4BMA:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: uvObd9Lph9ADs967J5aV-AEQPGlBVQsC X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODExMDAzMSBTYWx0ZWRfX83+QPcr4DCYE xhbWKYnXXJMFoM06mzEMr0C898pl/ceQ3DJHleVEjAhEEvFd90FSHys7A26NJ352l+ijg7CNbXH 3DgOxdMdRFT8RsxXj8GDBMqRFIh9a9J6KTI22JenN1NXWTOmuAxN5l5VKWpj+/mdOu9zXZ7FQVc j2qd6a94TJlu6qQ8TUobzNIL0aakXdyzci1fsqe8b6xq3jAvacSX0a1PKFbUuDwFq0nzS3gUgCl qDZGoNqWAmRsbCg+YEE+F7iz5Mme50gTzEdMglNsoWxKBmF/rm8rgNipE/8QHD9QPKw/3BTBRlo DeT84C5qwzRi7z0/I6dXHiKONxS40e21/eDh/VjA/+n3h6B1bhsKTiY3erYrFA61tPBQPSRwZqv EvrhmNngw4LizQIAAIlrHtfwnYODbiwQfwDR95bk+/mhvUIlB7sgFWavkkTcUKbqoVutRNobmU8 jTC+d/qDf4A6CIwABnQ== X-Proofpoint-ORIG-GUID: uvObd9Lph9ADs967J5aV-AEQPGlBVQsC X-Proofpoint-Spam-Info: AW1haW4tMjYwODExMDAzMSBTYWx0ZWRfX5daGqX6rmPcc qBbRqET6shuhCv9WJzs0iMIq/99HPqyhFQPwuRtST2c0ymPHi0aXxJj543wqgZigwkDy0fEB8GG SToF+Rap9D2+l6W6rhi6uy6sPjB7EyQ= 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=2026-08-10_06,2026-08-10_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 suspectscore=0 adultscore=0 lowpriorityscore=0 clxscore=1015 priorityscore=1501 impostorscore=0 phishscore=0 spamscore=0 bulkscore=0 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608110031 On 03/08/26 6:40 pm, Venkat Rao Bagalkote wrote: > Hi, > > We are seeing random userspace crashes while building the kernel on > ppc64le when running recent upstream/mainline or linux-next kernels. > > The failures occur in different userspace programs, but the crash > signature is consistently inside ld64.so.2. > > Environment > ----------- > > Architecture: >   ppc64le > > Platform: >   IBM Power systems (LPAR) > > Userspace: >   RHEL userspace > > Workload: >   Kernel build > >     make -j32 -s && make modules_install && make install > > > gcc version 14.3.1 20251022 (Red Hat 14.3.1-4) (GCC) > > GNU ld version 2.41-63.el10 > ldd (GNU libc) 2.39 > > > > > Observation > ----------- > > The issue is observed when the system is booted with recent upstream > kernels. > > The same LPAR, userspace, toolchain, and source tree are able to build > successfully when booted with the base OS kernel. > > Typical failures include: > >   sh >   fixdep >   make > > The source file being compiled when the failure occurs varies from run > to run. > > Examples > -------- > > Example 1: > > [ 1277.872746] fixdepsegfault (11) at 29ac0 > [ 1277.872746] fixdep[122982]: nip 3fffbebd8214 lr 3fffbebd7358 > [ 1277.872746] fixdep[122982]: code 1 in ld64.sofffbeba1000+50000] > > [ 1277.872793] fixdepcode: > f90104a8 7ce903a6 f9410060 f9490008 > f9490010 f9490018 39290020 f9490000 > > [ 1277.872805] fixdep[122982[37214,3fffbeba1000+50000 f9490018 > 7e731050 f9410030 fa610020 > > cripts/Makefile.build:289: > drivers/gpu/drm/amd/amdgpu/../pm/powerplay/smumgr/vegam_smumgr.o] > Error 139 > > Example 2: > > [Sun Aug 2 12:36:38 2026] sh[115552]: segfaultbcd0 > nip 3fffbd73d004 lr 3fffbd73c148 code 1 in > ld64.so.2[35004,3fffbd708000+4d000] > > Example 3: > > [Sun Aug 2 12:40:08 2026] fixdep[134469]: segfault (11) at > 2bcd0c3ca004 lr 3fff8c3c9148 code 1 in > ld64.so.2[35004,3fff8c395000+4d000] > > Example 4: > > [Mon Aug 3 05:44:20 2026] make[600291]: segfault (11) ip 3fffaf3b5004 > lr 3fffaf3b4148 code 1 in > ld64.so.2[35004,3fffaf380000+4d000] > > Notes > ----- > > - The crashing executable varies (sh, fixdep, make, etc.). > - The object file being compiled also varies. > - The crash always appears to occur in ld64.so.2. > - The issue has been observed on more than one system. > - A fresh OS installation with ample free memory reproduces the issue. > > Let me know, if any more info is needed. > > If you happen to fix this issue, please add below tag. > > Reported-by: Venkat Rao Bagalkote > > > As part of debugging and suggested by Maddy, I reverted the following commit:   263e5159e00a ("powerpc: Fix exit_flags field placement in pt_regs for ptrace") and rebuilt/booted linux-next with only that change reverted. After booting the reverted kernel, I rebuilt the latest upstream kernel using the same userspace and toolchain. The build completed successfully and I did not observe any of the ld64.so.2 userspace segfaults that were previously seen during kernel compilation. Kernel used for testing:   7.2.0-rc5-next-20260731-00001-g79d9c1ce90a9 Top of tree:   commit 79d9c1ce90a9873422ca4d6d0124a1d1c10a098c   Revert "powerpc: Fix exit_flags field placement in pt_regs for ptrace" The upstream kernel build completed successfully:   INSTALL /lib/modules/7.2.0-rc7/kernel/net/openvswitch/vport-gre.ko   DEPMOD  /lib/modules/7.2.0-rc7   INSTALL /boot Based on this testing, reverting commit 263e5159e00a appears to eliminate the random userspace crashes observed during kernel builds, suggesting that the issue may be related to that change. > > > Thanks, > Venkat.