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>
---
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 addfae2f63ef..e0e2c4a943e4 100644
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -2622,16 +2622,18 @@ 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;
}
--
2.42.0.609.gbb76f46606-goog
