| 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
| ||
|
Message-ID: <20260205205622.530825-1-irogers@google.com>
Date: Thu, 5 Feb 2026 12:56:21 -0800
From: Ian Rogers <irogers@...gle.com>
To: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>, Namhyung Kim <namhyung@...nel.org>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>,
Ian Rogers <irogers@...gle.com>, Adrian Hunter <adrian.hunter@...el.com>,
James Clark <james.clark@...aro.org>, Andi Kleen <ak@...ux.intel.com>,
Dmitry Vyukov <dvyukov@...gle.com>,
"Krzysztof Łopatowski" <krzysztof.m.lopatowski@...il.com>, linux-perf-users@...r.kernel.org,
linux-kernel@...r.kernel.org, Dapeng Mi <dapeng1.mi@...ux.intel.com>,
Weilin Wang <weilin.wang@...el.com>
Subject: [PATCH v1 1/2] perf callchain lbr: Make the leaf IP that of the sample
The current IP of a leaf function when reported from a perf record
with "--call-graph lbr" is the "to" field of the LBR branch stack
record. The sample for the event being recorded may be further into
the function and there may be inlining information associated with
it. Rather than use the branch stack "to" field in this case switch to
the callchain appending the sample->ip and thereby allowing the inline
information to show.
Before this change:
```
$ perf record --call-graph lbr perf test -w inlineloop
...
$ perf script --fields +srcline
...
perf-inlineloop 467586 4649.344493: 950905 cpu_core/cycles/P:
55dfda2829c0 parent+0x0 (perf)
inlineloop.c:31
55dfda282a96 inlineloop+0x86 (perf)
inlineloop.c:47
55dfda236420 run_workload+0x59 (perf)
builtin-test.c:715
55dfda236b03 cmd_test+0x413 (perf)
builtin-test.c:825
...
```
After this change:
```
$ perf record --call-graph lbr perf test -w inlineloop
...
$ perf script --fields +srcline
...
perf-inlineloop 529703 11878.680815: 950905 cpu_core/cycles/P:
555ce86be9e6 leaf+0x26
inlineloop.c:20 (inlined)
555ce86be9e6 middle+0x26
inlineloop.c:27 (inlined)
555ce86be9e6 parent+0x26 (perf)
inlineloop.c:32
555ce86bea96 inlineloop+0x86 (perf)
inlineloop.c:47
555ce8672420 run_workload+0x59 (perf)
builtin-test.c:715
555ce8672b03 cmd_test+0x413 (perf)
builtin-test.c:825
...
```
Signed-off-by: Ian Rogers <irogers@...gle.com>
---
tools/perf/util/machine.c | 20 ++++++++++++++++----
1 file changed, 16 insertions(+), 4 deletions(-)
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 5b0f5a48ffd4..e76f8c86e62a 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2423,8 +2423,14 @@ static int lbr_callchain_add_lbr_ip(struct thread *thread,
}
if (callee) {
- /* Add LBR ip from first entries.to */
- ip = entries[0].to;
+ /*
+ * Set the (first) leaf function's IP to sample->ip (the
+ * location of the sample) but if not recorded use entries.to
+ */
+ if (sample->ip)
+ ip = sample->ip;
+ else
+ ip = entries[0].to;
flags = &entries[0].flags;
*branch_from = entries[0].from;
err = add_callchain_ip(thread, cursor, parent,
@@ -2477,8 +2483,14 @@ static int lbr_callchain_add_lbr_ip(struct thread *thread,
}
if (lbr_nr > 0) {
- /* Add LBR ip from first entries.to */
- ip = entries[0].to;
+ /*
+ * Set the (first) leaf function's IP to sample->ip (the
+ * location of the sample) but if not recorded use entries.to
+ */
+ if (sample->ip)
+ ip = sample->ip;
+ else
+ ip = entries[0].to;
flags = &entries[0].flags;
*branch_from = entries[0].from;
err = add_callchain_ip(thread, cursor, parent,
--
2.53.0.rc2.204.g2597b5adb4-goog
Powered by blists - more mailing lists