linux-kernel - [PATCHSET v3 0/5] perf tools: Add deferred callchain support

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [thread-next>] [day] [month] [year] [list]
Message-ID: <20251114070018.160330-1-namhyung@kernel.org>
Date: Thu, 13 Nov 2025 23:00:13 -0800
From: Namhyung Kim <namhyung@...nel.org>
To: Arnaldo Carvalho de Melo <acme@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	James Clark <james.clark@...aro.org>
Cc: Jiri Olsa <jolsa@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	linux-perf-users@...r.kernel.org,
	Steven Rostedt <rostedt@...dmis.org>,
	Josh Poimboeuf <jpoimboe@...nel.org>,
	Indu Bhagat <indu.bhagat@...cle.com>,
	Jens Remus <jremus@...ux.ibm.com>,
	Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
	linux-trace-kernel@...r.kernel.org,
	bpf@...r.kernel.org
Subject: [PATCHSET v3 0/5] perf tools: Add deferred callchain support

Hello,

This is a new version of deferred callchain support as the kernel part
is merged to the tip tree.  Actually this is based on Steve's work (v16).

  https://lore.kernel.org/r/20250908175319.841517121@kernel.org

This version has the following changes.

* handle new attr.defer_output to generate deferred callchains
* fix crash when cookies don't match  (Steven)
* disable merging for perf inject
* fix missing feature detection bug
* symbolize merged callchains properly

Here's an example session.

  $ perf record -g pwd
  /home/namhyung/project/linux
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.010 MB perf.data (29 samples) ]
  
  $ perf evlist -v
  cpu/cycles/P: type: 0 (PERF_TYPE_HARDWARE), size: 136, config: 0 (PERF_COUNT_HW_CPU_CYCLES),
  { sample_period, sample_freq }: 4000, sample_type: IP|TID|TIME|CALLCHAIN|PERIOD,
  read_format: ID|LOST, disabled: 1, inherit: 1, mmap: 1, comm: 1, freq: 1, enable_on_exec: 1,
  task: 1, sample_id_all: 1, mmap2: 1, comm_exec: 1, ksymbol: 1, bpf_event: 1, build_id: 1,
  defer_callchain: 1, defer_output: 1
  
  $ perf script
  ...
  pwd    2312   121.163435:     249113 cpu/cycles/P:
          ffffffff845b78d8 __build_id_parse.isra.0+0x218 ([kernel.kallsyms])
          ffffffff83bb5bf6 perf_event_mmap+0x2e6 ([kernel.kallsyms])
          ffffffff83c31959 mprotect_fixup+0x1e9 ([kernel.kallsyms])
          ffffffff83c31dc5 do_mprotect_pkey+0x2b5 ([kernel.kallsyms])
          ffffffff83c3206f __x64_sys_mprotect+0x1f ([kernel.kallsyms])
          ffffffff845e6692 do_syscall_64+0x62 ([kernel.kallsyms])
          ffffffff8360012f entry_SYSCALL_64_after_hwframe+0x76 ([kernel.kallsyms])
              7f18fe337fa7 mprotect+0x7 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
              7f18fe330e0f _dl_sysdep_start+0x7f (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
              7f18fe331448 _dl_start_user+0x0 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
  ...

  $ perf script --no-merge-callchains
  ...
  pwd    2312   121.163435:     249113 cpu/cycles/P:
          ffffffff845b78d8 __build_id_parse.isra.0+0x218 ([kernel.kallsyms])
          ffffffff83bb5bf6 perf_event_mmap+0x2e6 ([kernel.kallsyms])
          ffffffff83c31959 mprotect_fixup+0x1e9 ([kernel.kallsyms])
          ffffffff83c31dc5 do_mprotect_pkey+0x2b5 ([kernel.kallsyms])
          ffffffff83c3206f __x64_sys_mprotect+0x1f ([kernel.kallsyms])
          ffffffff845e6692 do_syscall_64+0x62 ([kernel.kallsyms])
          ffffffff8360012f entry_SYSCALL_64_after_hwframe+0x76 ([kernel.kallsyms])
                 b00000006 [unknown] ([unknown])
      
  pwd    2312   121.163447: DEFERRED CALLCHAIN
              7f18fe337fa7 mprotect+0x7 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
              7f18fe330e0f _dl_sysdep_start+0x7f (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
              7f18fe331448 _dl_start_user+0x0 (/lib/x86_64-linux-gnu/ld-linux-x86-64.so.2)
  ...

The code is available at 'perf/defer-callchain-v3' branch in

  git.kernel.org/pub/scm/linux/kernel/git/namhyung/linux-perf.git

Thanks,
Namhyung


Namhyung Kim (5):
  tools headers UAPI: Sync linux/perf_event.h for deferred callchains
  perf tools: Minimal DEFERRED_CALLCHAIN support
  perf record: Enable defer_callchain for user callchains
  perf script: Display PERF_RECORD_CALLCHAIN_DEFERRED
  perf tools: Merge deferred user callchains

 tools/include/uapi/linux/perf_event.h     | 21 +++++-
 tools/lib/perf/include/perf/event.h       |  8 ++
 tools/perf/Documentation/perf-script.txt  |  5 ++
 tools/perf/builtin-inject.c               |  1 +
 tools/perf/builtin-report.c               |  1 +
 tools/perf/builtin-script.c               | 92 +++++++++++++++++++++++
 tools/perf/util/callchain.c               | 29 +++++++
 tools/perf/util/callchain.h               |  3 +
 tools/perf/util/event.c                   |  1 +
 tools/perf/util/evlist.c                  |  1 +
 tools/perf/util/evlist.h                  |  2 +
 tools/perf/util/evsel.c                   | 43 +++++++++++
 tools/perf/util/evsel.h                   |  1 +
 tools/perf/util/machine.c                 |  1 +
 tools/perf/util/perf_event_attr_fprintf.c |  2 +
 tools/perf/util/sample.h                  |  2 +
 tools/perf/util/session.c                 | 85 +++++++++++++++++++++
 tools/perf/util/tool.c                    |  2 +
 tools/perf/util/tool.h                    |  4 +-
 19 files changed, 302 insertions(+), 2 deletions(-)

-- 
2.52.0.rc1.455.g30608eb744-goog