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Marchesi" , Beau Belgrave , Linus Torvalds , Andrew Morton , Florian Weimer , Sam James , Kees Cook , "Carlos O'Donell" , Arnaldo Carvalho de Melo , Peter Zijlstra References: <20250908175319.841517121@kernel.org> <20250908175430.639412649@kernel.org> <20251002134938.756db4ef@gandalf.local.home> <20251024130203.GC3245006@noisy.programming.kicks-ass.net> Content-Language: en-US From: Jens Remus Organization: IBM Deutschland Research & Development GmbH In-Reply-To: <20251024130203.GC3245006@noisy.programming.kicks-ass.net> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-GUID: L_7sfh61mwnig6fGCcLLmEZrHnaQHDuI X-Proofpoint-ORIG-GUID: L_7sfh61mwnig6fGCcLLmEZrHnaQHDuI X-Authority-Analysis: v=2.4 cv=VMPQXtPX c=1 sm=1 tr=0 ts=69145c0b cx=c_pps a=3Bg1Hr4SwmMryq2xdFQyZA==:117 a=3Bg1Hr4SwmMryq2xdFQyZA==:17 a=IkcTkHD0fZMA:10 a=6UeiqGixMTsA:10 a=VkNPw1HP01LnGYTKEx00:22 a=VnNF1IyMAAAA:8 a=VwQbUJbxAAAA:8 a=Vs_kanKWfxrV1IkLjT4A:9 a=3ZKOabzyN94A:10 a=QEXdDO2ut3YA:10 a=nl4s5V0KI7Kw-pW0DWrs:22 a=pHzHmUro8NiASowvMSCR:22 a=xoEH_sTeL_Rfw54TyV31:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjUxMTA4MDAyMiBTYWx0ZWRfX9yuxxvyN78Og 69SPfChu8C26Ui7EH/rN9p/nPA8ApOGKgjl3fx4SMJtdZ0NkHEHvL573DxDpej4bUkc6Vw25+pC xFy74vg0QORXjXqQekG6shZ5IPcDavRtDxY/8MtXSt4ph69AFwTGBPpqT6yzyfdRmFR01xD2Gtv bk0il8sBGlxnJURQW0pvPa4JYOnzSlYKi4e+WVOxwIPof/1+ziwe4hQvuofMRrwzPdyglHF3H02 IchSUpkPcjvPuZbbO3veyqynNcwRL0bm3Wu5qtA3YPJdvmMdQvF/je4LMDkPbF3wDpGNVt1fWrZ sbc6etbnf9FULaU1o/N91tHnSOrqVYnzRNOuF4b3hG4lU8ye/hYDRu+qvgNNY8Oefwg8OiQEFjA Y60tXmEVofdQJHIkppKmjPZhQv8f5w== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.9,FMLib:17.12.100.49 definitions=2025-11-12_03,2025-11-11_03,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 impostorscore=0 priorityscore=1501 lowpriorityscore=0 bulkscore=0 clxscore=1015 phishscore=0 spamscore=0 malwarescore=0 adultscore=0 suspectscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.19.0-2510240000 definitions=main-2511080022 Hello Namhyung, could you please adapt your patches from this series to Peter's latest changes to unwind user and related perf support, especially his new version c69993ecdd4d ("perf: Support deferred user unwind") available at: git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git perf/core On 10/24/2025 3:02 PM, Peter Zijlstra wrote: > On Thu, Oct 02, 2025 at 01:49:38PM -0400, Steven Rostedt wrote: >> On Mon, 08 Sep 2025 13:53:23 -0400 >> Steven Rostedt wrote: >> >>> +static int evlist__deliver_deferred_samples(struct evlist *evlist, >>> + const struct perf_tool *tool, >>> + union perf_event *event, >>> + struct perf_sample *sample, >>> + struct machine *machine) >>> +{ >>> + struct deferred_event *de, *tmp; >>> + struct evsel *evsel; >>> + int ret = 0; >>> + >>> + if (!tool->merge_deferred_callchains) { >>> + evsel = evlist__id2evsel(evlist, sample->id); >>> + return tool->callchain_deferred(tool, event, sample, >>> + evsel, machine); >>> + } >>> + >>> + list_for_each_entry_safe(de, tmp, &evlist->deferred_samples, list) { >>> + struct perf_sample orig_sample; >> >> orig_sample is not initialized and can then contain junk. >> >>> + >>> + ret = evlist__parse_sample(evlist, de->event, &orig_sample); >>> + if (ret < 0) { >>> + pr_err("failed to parse original sample\n"); >>> + break; >>> + } >>> + >>> + if (sample->tid != orig_sample.tid) >>> + continue; >>> + >>> + if (event->callchain_deferred.cookie == orig_sample.deferred_cookie) >>> + sample__merge_deferred_callchain(&orig_sample, sample); >> >> The sample__merge_deferred_callchain() initializes both >> orig_sample.deferred_callchain and the callchain. But now that it's not >> being called, it can cause the below free to happen with junk as the >> callchain. This needs: >> >> else >> orig_sample.deferred_callchain = false; > > Ah, so I saw crashes from here and just deleted both free()s and got on > with things ;-) This needs to be properly resolved. In the meantime I am using Steven's suggestion above to continue my work on unwind user sframe (s390). > >>> + >>> + evsel = evlist__id2evsel(evlist, orig_sample.id); >>> + ret = evlist__deliver_sample(evlist, tool, de->event, >>> + &orig_sample, evsel,> machine); + >>> + if (orig_sample.deferred_callchain) >>> + free(orig_sample.callchain); >>> + >>> + list_del(&de->list); >>> + free(de); >>> + >>> + if (ret) >>> + break; >>> + } >>> + return ret; >>> +} >> >> -- Steve Thanks and regards, Jens -- Jens Remus Linux on Z Development (D3303) +49-7031-16-1128 Office jremus@de.ibm.com IBM IBM Deutschland Research & Development GmbH; Vorsitzender des Aufsichtsrats: Wolfgang Wendt; Geschäftsführung: David Faller; Sitz der Gesellschaft: Böblingen; Registergericht: Amtsgericht Stuttgart, HRB 243294 IBM Data Privacy Statement: https://www.ibm.com/privacy/