[PATCH 6.18 004/752] perf unwind-libdw: Fix invalid reference counts

Sasha Levin
2026-02-28T17:47:57Z

From: Ian Rogers <irogers@google.com>

[ Upstream commit f815fc0c66e777c727689666cfb46b8d461c2f99 ]

The addition of addr_location__exit() causes use-after put on the maps
and map references in the unwind info. Add the gets and then add the
map_symbol__exit() calls.

Fixes: 0dd5041c9a0eaf8c ("perf addr_location: Add init/exit/copy functions")
Reviewed-by: James Clark <james.clark@linaro.org>
Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Howard Chu <howardchu95@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephen Brennan <stephen.s.brennan@oracle.com>
Cc: Tony Jones <tonyj@suse.de>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/perf/util/unwind-libdw.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/unwind-libdw.c b/tools/perf/util/unwind-libdw.c
index ae70fb56a0572..3ff427a49e4c5 100644
--- a/tools/perf/util/unwind-libdw.c
+++ b/tools/perf/util/unwind-libdw.c
@@ -136,8 +136,8 @@ static int entry(u64 ip, struct unwind_info *ui)
}

e->ip = ip;
- e->ms.maps = al.maps;
- e->ms.map = al.map;
+ e->ms.maps = maps__get(al.maps);
+ e->ms.map = map__get(al.map);
e->ms.sym = al.sym;

pr_debug("unwind: %s:ip = 0x%" PRIx64 " (0x%" PRIx64 ")\n",
@@ -325,6 +325,9 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg,
if (err)
pr_debug("unwind: failed with '%s'\n", dwfl_errmsg(-1));

+ for (i = 0; i < ui->idx; i++)
+ map_symbol__exit(&ui->entries[i].ms);
+
dwfl_end(ui->dwfl);
free(ui);
return 0;
--
2.51.0