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From:   Ben Gainey <ben.gainey@arm.com>
To:     linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org
Cc:     peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
        mark.rutland@arm.com, alexander.shishkin@linux.intel.com,
        jolsa@kernel.org, namhyung@kernel.org, irogers@google.com,
        adrian.hunter@intel.com, Ben Gainey <ben.gainey@arm.com>
Subject: [PATCH] tools/perf: Fix missing reference count get in call_path_from_sample
Date:   Thu,  7 Dec 2023 14:09:11 +0000
Message-ID: <20231207140911.3240408-1-ben.gainey@arm.com>
MIME-Version: 1.0
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Precedence: bulk

The addr_location map and maps fields in the inner loop were missing
calls to map__get/maps__get. The subsequent addr_location__exit call in
each loop puts the map/maps fields causing use-after-free aborts.

This issue reproduces on at least arm64 and x86_64 with something
simple like `perf record -g ls` followed by `perf script -s script.py`
with the following script:

    perf_db_export_mode = True
    perf_db_export_calls = False
    perf_db_export_callchains = True

    def sample_table(*args):
        print(f'sample_table({args})')

    def call_path_table(*args):
        print(f'call_path_table({args}')

Fixes: 0dd5041c9a0ea ("perf addr_location: Add init/exit/copy functions")
Signed-off-by: Ben Gainey <ben.gainey@arm.com>
---
 tools/perf/util/db-export.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/perf/util/db-export.c b/tools/perf/util/db-export.c
index b9fb71ab7a73..106429155c2e 100644
--- a/tools/perf/util/db-export.c
+++ b/tools/perf/util/db-export.c
@@ -253,8 +253,8 @@ static struct call_path *call_path_from_sample(struct db_export *dbe,
 		 */
 		addr_location__init(&al);
 		al.sym = node->ms.sym;
-		al.map = node->ms.map;
-		al.maps = thread__maps(thread);
+		al.map = map__get(node->ms.map);
+		al.maps = maps__get(thread__maps(thread));
 		al.addr = node->ip;
 
 		if (al.map && !al.sym)
-- 
2.43.0