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Wed, 6 Aug 2025 09:29:25 GMT Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 554962004B; Wed, 6 Aug 2025 09:29:25 +0000 (GMT) Received: from smtpav06.fra02v.mail.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 1D41F20049; Wed, 6 Aug 2025 09:29:25 +0000 (GMT) Received: from [9.152.212.130] (unknown [9.152.212.130]) by smtpav06.fra02v.mail.ibm.com (Postfix) with ESMTP; Wed, 6 Aug 2025 09:29:25 +0000 (GMT) Message-ID: <1094385e-6f86-453f-a48e-fa284dcae385@linux.ibm.com> Date: Wed, 6 Aug 2025 11:29:24 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/2] perf bpf-filter: Enable events manually To: Alexander Gordeev , Ilya Leoshkevich Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Ian Rogers , Arnaldo Carvalho de Melo , bpf@vger.kernel.org, linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org, linux-s390@vger.kernel.org, Jiri Olsa , Heiko Carstens , Vasily Gorbik References: <20250805130346.1225535-1-iii@linux.ibm.com> <20250805130346.1225535-3-iii@linux.ibm.com> <4a7fc5ab-682d-4fac-a547-9e4b1263dba7-agordeev@linux.ibm.com> Content-Language: en-US From: Thomas Richter Organization: IBM In-Reply-To: <4a7fc5ab-682d-4fac-a547-9e4b1263dba7-agordeev@linux.ibm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: kp9R7gzU3Zi2X7pQoZH8W3IiFwi5wq4p X-Authority-Analysis: v=2.4 cv=F/xXdrhN c=1 sm=1 tr=0 ts=6893207b cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=IkcTkHD0fZMA:10 a=2OwXVqhp2XgA:10 a=G2SI-qYk9hsPBJNDFb0A:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 X-Proofpoint-GUID: ByIXSOgnBIEuNgtdSnszCEELpYo7LbV2 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUwODA2MDA1NyBTYWx0ZWRfX9KfYdHqR9GDI Y2nmdZvmxcwpHVRRulqqUvZ/FZDuaJdIwkz0Y49tMESj0+S4foX1OPBQODR/GBsGCZiZWOV83Jg 4MHJtU0tnHYnzRRqTJxPTRZN+NjejH5JlO9TvxoSeHdc6/WUj8mVU4OgiY0TY4dHbytC31VHenu bYuRTzMeoeEDlHNUrDA4hkTZhGd39n5xvGIjh/ZGyzl04OEiQCaPQrKRTyuWo17nLwvgCtOYF0N sEHjrwGYun/eXu5tzHekJbAV/DBJcI5YBrrYPqdMVS0+8GH9BjY8kdR3yIfi1v5OyJPkb9WJoRy FEMzme1beyqrWepAiCHI5tZ1QpcRJYMegIKnaw8U+b1R3CdW0cle3VuL+zbG/9q9uOplNJFgC9x 9U2fWXqD1febnrQrbnHXJe87s6Mcmf51xTteJ7roawXuUuJ1AYu83JtOdAuwAnedbXSFWubo X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1099,Hydra:6.1.9,FMLib:17.12.80.40 definitions=2025-08-06_02,2025-08-04_01,2025-03-28_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 mlxscore=0 lowpriorityscore=0 priorityscore=1501 impostorscore=0 clxscore=1015 spamscore=0 bulkscore=0 adultscore=0 mlxlogscore=999 malwarescore=0 phishscore=0 suspectscore=0 classifier=spam authscore=0 authtc=n/a authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2507300000 definitions=main-2508060057 On 8/5/25 16:14, Alexander Gordeev wrote: > On Tue, Aug 05, 2025 at 02:54:05PM +0200, Ilya Leoshkevich wrote: > > Hi Thomas, > > The below comments date to the initial version, so the question is > rather to you: > >> On linux-next > > This line is extra. I just wanted to let readers know which repo to look at. > >> commit b4c658d4d63d61 ("perf target: Remove uid from target") >> introduces a regression on s390. In fact the regression exists >> on all platforms when the event supports auxiliary data gathering. > > So which commit it actually fixes: the above, the below or the both? > >> Fixes: 63f2f5ee856ba ("libbpf: add ability to attach/detach BPF program to perf event") > > Thanks! > Good question! Pick what you like... :-) The issue in question originates from a patch set of 10 patches. The patch set rebuilds event sample with filtering and migrates from perf tool's selective process picking to more generic eBPF filtering using eBPF programs hooked to perf events. To be precise, the issue Ilya's patch fixes is this: Fixes: 63f2f5ee856ba ("libbpf: add ability to attach/detach BPF program to perf event") However the issue (perf failure) does *NOT* show up until this patch is applied: commit b4c658d4d63d61 ("perf target: Remove uid from target") There are some patches in between the two (when you look at the complete patch set), but they do not affect the result. Hope that helps. -- Thomas Richter, Dept 3303, IBM s390 Linux Development, Boeblingen, Germany -- IBM Deutschland Research & Development GmbH Vorsitzender des Aufsichtsrats: Wolfgang Wendt Geschäftsführung: David Faller Sitz der Gesellschaft: Böblingen / Registergericht: Amtsgericht Stuttgart, HRB 243294