6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Ian Rogers <irogers@xxxxxxxxxx>
[ Upstream commit ab8ce150781d326c6bfbe1e09f175ffde1186f80 ]
Running perf top with address sanitizer and "--call-graph=lbr" fails
due to reading sample 0 when no samples exist. Add a guard to prevent
this.
Fixes: e2b23483eb1d ("perf machine: Factor out lbr_callchain_add_lbr_ip()")
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
Cc: K Prateek Nayak <kprateek.nayak@xxxxxxx>
Cc: Ravi Bangoria <ravi.bangoria@xxxxxxx>
Cc: Sandipan Das <sandipan.das@xxxxxxx>
Cc: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: German Gomez <german.gomez@xxxxxxx>
Cc: James Clark <james.clark@xxxxxxx>
Cc: Nick Terrell <terrelln@xxxxxx>
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: Changbin Du <changbin.du@xxxxxxxxxx>
Cc: liuwenyu <liuwenyu7@xxxxxxxxxx>
Cc: Yang Jihong <yangjihong1@xxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Miguel Ojeda <ojeda@xxxxxxxxxx>
Cc: Song Liu <song@xxxxxxxxxx>
Cc: Leo Yan <leo.yan@xxxxxxxxxx>
Cc: Kajol Jain <kjain@xxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
Cc: Athira Rajeev <atrajeev@xxxxxxxxxxxxxxxxxx>
Cc: Yanteng Si <siyanteng@xxxxxxxxxxx>
Cc: Liam Howlett <liam.howlett@xxxxxxxxxx>
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20231024222353.3024098-3-irogers@xxxxxxxxxx
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
tools/perf/util/machine.c | 22 ++++++++++++----------
1 file changed, 12 insertions(+), 10 deletions(-)
diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 88f31b3a63acb..e6a8d758f6fe4 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2624,16 +2624,18 @@ static int lbr_callchain_add_lbr_ip(struct thread *thread,
save_lbr_cursor_node(thread, cursor, i);
}
- /* Add LBR ip from first entries.to */
- ip = entries[0].to;
- flags = &entries[0].flags;
- *branch_from = entries[0].from;
- err = add_callchain_ip(thread, cursor, parent,
- root_al, &cpumode, ip,
- true, flags, NULL,
- *branch_from);
- if (err)
- return err;
+ if (lbr_nr > 0) {
+ /* Add LBR ip from first entries.to */
+ ip = entries[0].to;
+ flags = &entries[0].flags;
+ *branch_from = entries[0].from;
+ err = add_callchain_ip(thread, cursor, parent,
+ root_al, &cpumode, ip,
+ true, flags, NULL,
+ *branch_from);
+ if (err)
+ return err;
+ }
return 0;
}
--
2.42.0
