From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pg1-f201.google.com (mail-pg1-f201.google.com [209.85.215.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7E4E0253B42 for ; Mon, 1 Dec 2025 20:55:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.215.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764622521; cv=none; b=E7MiyTk+sk7yCyAyX68c3gNMooMTZ/qTa+Hl3VYk3LvUQq3RK7kGaeq+8SZOsyNFzt6rIT3yxxJOLUipocasnpX96ZaT2oLT1ldYvO6iSsSMEdeJsocmkPi7BbQXnl3Btue+KztWBxSG4XSw7ik7beSLOW+Pp6AbJ5sFytSXROM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764622521; c=relaxed/simple; bh=ZSxrOdUDV2fsiZ8VTAoHybN58iPShWXHilNcC1eOP9c=; h=Date:Mime-Version:Message-ID:Subject:From:To:Content-Type; b=oGjkgINQuzLnE0nDvp/PBtmscqGx57IUyhGty9OckgXw7btg1Z/zF4llR46W9bWBniW8teB5g5g2s1Yk//ylOBQDoU9QpSmBEmF2OLH5m0v8tDbuGVGiGLr5y7/GfDo5NLXteUIYgZGOqWqaeb8pzUc1neKVe+tJnifdlJN68tA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=T+snBJLN; arc=none smtp.client-ip=209.85.215.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--irogers.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="T+snBJLN" Received: by mail-pg1-f201.google.com with SMTP id 41be03b00d2f7-b6097ca315bso6744024a12.3 for ; Mon, 01 Dec 2025 12:55:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1764622518; x=1765227318; darn=vger.kernel.org; h=to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=CM4WlM3X7MrnLioK5/Fb9PLY7pS2paWGYqO8IZMvjl0=; b=T+snBJLNwzOKpEO3egsltT6gbaTW7afXQzbRwKrR8DshTxxuCwrBxdLW0rLZUiLkjw Cyj3vp7Elc+wDJykWAzEwiZzOO0Ir/5lfQb7FuEeGBzaOcavG9Li6YP1kBCmUFviqKvl EZ7UqIbVaI0+zFMQ7974DL7QTq3qpY1lg62jPDkHx6cNBA4fga3HcrzJh1Xms9Q+g6HN thfB3wGrDZwMujp2X+YvA2iD4pkDY/46WMg+5hgvK+PrmcdJeF5AvabTCsR2Qc2n9LCw HlLbT+FK5MJuH2Om7egKdamnGC37aA462AHyv9SyPCu6qirdbUE5if+yxeyW2YeWxy1z mpvw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1764622518; x=1765227318; h=to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=CM4WlM3X7MrnLioK5/Fb9PLY7pS2paWGYqO8IZMvjl0=; b=Mmkkvv9gtaAyB14lMXVHhbRVx70K1pgn4lMd0hQSH3pnkFEMp0VoyZm7y3ZsFyoyMa QaPuMb0fLCVmyXqZ5dxMFHmDIvrxfXWCBte+ho0NfxxdTtSSflHjFaRD1d0cBb8HSgbR OFcLVpTOP6ekMJgd97vsNilmz9Vtsmoz2zkPjSlv2v9e28GqAPmc9D4bE38a30P/dySk mAiPgwNaiM2nBcqezoYyBXZza8Xwo3mYDqtoQrZbe8JcC75/GRNsPSZLYSx/uDdHEnsF jHK0EUslNTpaWQC4RGdj3MJ/TdY8y5o0ZiEQ6Ii9TWT8FUFFATBZQBLBRpd3jL46lHVv kgAg== X-Forwarded-Encrypted: i=1; AJvYcCWEfbabjPZCJOMec7dPTkK5NBUFGCNck6yagPeX1FZbKf3bHu+g5zim6pbbKnxnDSrrtS0OF/wfUpq0fyYLcolw@vger.kernel.org X-Gm-Message-State: AOJu0YyMn5xvvqxTGsNendYC27uqSGuDoEa9ac2gyNuYiNTnZCvNih/g AN7d4HRfAtc92n8k8NiixnZ/2MZ03r7HQfK+sBeSH+w980PxHdFkanlX1gIBoNOQeRtSgAOoro8 lr2My6NxA2A== X-Google-Smtp-Source: AGHT+IHzasUWwoOoaBGRKrbmTLPwNDgHZhXRK6AamdUEgKNV5PIGt1TasBJ+i8LlW5NAIHXjG29VZyv13epx X-Received: from dlbtp11.prod.google.com ([2002:a05:7022:3b8b:b0:119:49ca:6ba3]) (user=irogers job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7022:3898:b0:11b:7e61:57d5 with SMTP id a92af1059eb24-11c9d60eac9mr25543419c88.2.1764622517699; Mon, 01 Dec 2025 12:55:17 -0800 (PST) Date: Mon, 1 Dec 2025 12:54:59 -0800 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Mailer: git-send-email 2.52.0.158.g65b55ccf14-goog Message-ID: <20251201205509.195451-1-irogers@google.com> Subject: [PATCH v2 00/10] perf: Refactor/add fallbacks for reading build-id and debuglink From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Namhyung Kim , Alexander Shishkin , Jiri Olsa , Ian Rogers , Adrian Hunter , Suzuki K Poulose , Mike Leach , James Clark , John Garry , Will Deacon , Leo Yan , Athira Rajeev , tanze , Stephen Brennan , Andi Kleen , Chun-Tse Shao , Thomas Falcon , Dapeng Mi , "Dr. David Alan Gilbert" , Christophe Leroy , "=?UTF-8?q?Krzysztof=20=C5=81opatowski?=" , "Masami Hiramatsu (Google)" , Alexandre Ghiti , Haibo Xu , Sergei Trofimovich , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Content-Type: text/plain; charset="UTF-8" This cleans up some tech debt mentioned in the thread: https://lore.kernel.org/lkml/aQt66zhfxSA80xwt@gentoo.org/ The perf tool has fallbacks for objdump but not in the case of build-id and debuglink reading. Refactor the code so that in the case of read_build_id it now looks like: ``` ... int filename__read_build_id(const char *filename, struct build_id *bid) { struct kmod_path m = { .name = NULL, }; char path[PATH_MAX]; int err, fd; if (!filename) return -EFAULT; if (!is_regular_file(filename)) return -EWOULDBLOCK; err = kmod_path__parse(&m, filename); if (err) return -1; if (m.comp) { int error = 0; fd = filename__decompress(filename, path, sizeof(path), m.comp, &error); if (fd < 0) { pr_debug("Failed to decompress (error %d) %s\n", error, filename); return -1; } lseek(fd, 0, SEEK_SET); filename = path; } else { fd = open(filename, O_RDONLY); if (fd < 0) { pr_debug("Failed to open %s\n", filename); return -1; } } err = libbfd__read_build_id(fd, filename, bid); if (err == 0) goto out; err = libelf__read_build_id(fd, filename, bid); if (err == 0) goto out; err = sym_min__read_build_id(fd, filename, bid); out: close(fd); if (m.comp) unlink(filename); return err; } ... ``` That is what was previously symbol-elf decompression code is now made common for all cases of reading. The handling of "is_regular_file" is now common. There is a clear fallback from libbfd to libelf to the symbol-minimal (sym_min) versions of the functions. To support this there is refactoring of code into a perf-libelf.c file, to follow patterns established for the capstone, LLVM and libbfd code. v2: Rebase, resolving merge conflict with James' removal of the block argument: https://lore.kernel.org/lkml/20251121-james-perf-non-block-v1-1-6ab2702ab573@linaro.org/ Add a patch fixing an issue with return values from filename__read_build_id. Some tweaks to the PPC arch__sym_update patch commit message and make it 64-bit only. Change the sysfs__read_build_id code combining the libelf and minimal implementations but avoiding the memory read overhead, avoiding a potential buffer overrun if the descsz was particularly large in a build ID note, avoid reads and just using seeks. v1: https://lore.kernel.org/lkml/20251123023225.8069-1-irogers@google.com/ Ian Rogers (10): perf symbol: Reduce scope of elf__needs_adjust_symbols perf symbol: Reduce scope of arch__sym_update perf symbol: Move libelf code to its own file/header perf symbol: Remove unused includes perf symbol: Move dso__load_bfd_symbols out of symbol.h perf symbol: Use fallbacks with filename__read_build_id perf symbol: Use fallbacks for filename__read_debuglink perf symbol: Make a common sysfs__read_build_id perf dso: Move type helpers out of symbol and use fallbacks perf symbol: Fix ENOENT case for filename__read_build_id tools/perf/arch/powerpc/util/sym-handling.c | 7 - tools/perf/builtin-annotate.c | 47 +-- tools/perf/builtin-buildid-cache.c | 6 +- tools/perf/builtin-c2c.c | 58 +-- tools/perf/builtin-diff.c | 22 +- tools/perf/builtin-inject.c | 19 +- tools/perf/builtin-kmem.c | 41 ++- tools/perf/builtin-kwork.c | 9 +- tools/perf/builtin-mem.c | 16 +- tools/perf/builtin-report.c | 76 ++-- tools/perf/builtin-sched.c | 50 ++- tools/perf/builtin-script.c | 89 ++--- tools/perf/builtin-timechart.c | 34 +- tools/perf/builtin-top.c | 85 +++-- tools/perf/builtin-trace.c | 82 ++--- .../scripts/python/Perf-Trace-Util/Context.c | 11 +- tools/perf/tests/code-reading.c | 1 + tools/perf/tests/hists_cumulate.c | 1 + tools/perf/tests/hists_filter.c | 1 + tools/perf/tests/hists_link.c | 1 + tools/perf/tests/hists_output.c | 1 + tools/perf/tests/mmap-thread-lookup.c | 1 + tools/perf/tests/pe-file-parsing.c | 5 +- tools/perf/util/Build | 6 +- tools/perf/util/annotate-data.c | 7 +- tools/perf/util/auxtrace.h | 1 + tools/perf/util/block-info.c | 11 +- tools/perf/util/build-id.c | 28 +- tools/perf/util/callchain.c | 1 + tools/perf/util/cs-etm.c | 1 + tools/perf/util/data-convert-json.c | 30 +- tools/perf/util/db-export.c | 16 +- tools/perf/util/dlfilter.c | 11 +- tools/perf/util/dlfilter.h | 1 + tools/perf/util/dso.c | 57 +-- tools/perf/util/event.c | 41 ++- tools/perf/util/evsel_fprintf.c | 14 +- tools/perf/util/hist.c | 29 +- tools/perf/util/intel-pt.c | 35 +- tools/perf/util/kvm-stat.h | 5 +- tools/perf/util/libbfd.c | 9 +- tools/perf/util/libbfd.h | 12 +- tools/perf/util/machine.c | 34 +- tools/perf/util/perf-libelf.c | 235 ++++++++++++ tools/perf/util/perf-libelf.h | 58 +++ tools/perf/util/print_insn.c | 14 +- tools/perf/util/probe-event.c | 1 + tools/perf/util/probe-finder.c | 1 + .../util/scripting-engines/trace-event-perl.c | 1 + .../scripting-engines/trace-event-python.c | 1 + tools/perf/util/symbol-elf.c | 338 +----------------- tools/perf/util/symbol-minimal.c | 166 +++++---- tools/perf/util/symbol-minimal.h | 13 + tools/perf/util/symbol.c | 107 +++++- tools/perf/util/symbol.h | 44 +-- tools/perf/util/symbol_fprintf.c | 1 + tools/perf/util/thread-stack.c | 12 +- tools/perf/util/thread.c | 18 +- tools/perf/util/unwind-libdw.c | 15 +- 59 files changed, 1079 insertions(+), 958 deletions(-) create mode 100644 tools/perf/util/perf-libelf.c create mode 100644 tools/perf/util/perf-libelf.h create mode 100644 tools/perf/util/symbol-minimal.h -- 2.52.0.158.g65b55ccf14-goog