6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Casey Chen <cachen@xxxxxxxxxxxxxxx>
[ Upstream commit 4c17736689ccfc44ec7dcc472577f25c34cf8724 ]
With 0dd5041c9a0e ("perf addr_location: Add init/exit/copy functions"),
when cpumode is 3 (macro PERF_RECORD_MISC_HYPERVISOR),
thread__find_map() could return with al->maps being NULL.
The path below could add a callchain_cursor_node with NULL ms.maps.
add_callchain_ip()
thread__find_symbol(.., &al)
thread__find_map(.., &al) // al->maps becomes NULL
ms.maps = maps__get(al.maps)
callchain_cursor_append(..., &ms, ...)
node->ms.maps = maps__get(ms->maps)
Then the path below would dereference NULL maps and get segfault.
fill_callchain_info()
maps__machine(node->ms.maps);
Fix it by checking if maps is NULL in fill_callchain_info().
Fixes: 0dd5041c9a0e ("perf addr_location: Add init/exit/copy functions")
Signed-off-by: Casey Chen <cachen@xxxxxxxxxxxxxxx>
Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>
Reviewed-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Acked-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: yzhong@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20240722211548.61455-1-cachen@xxxxxxxxxxxxxxx
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
tools/perf/util/callchain.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/perf/util/callchain.c b/tools/perf/util/callchain.c
index aee937d14fbbf..09e6b4e1401c9 100644
--- a/tools/perf/util/callchain.c
+++ b/tools/perf/util/callchain.c
@@ -1126,7 +1126,7 @@ int hist_entry__append_callchain(struct hist_entry *he, struct perf_sample *samp
int fill_callchain_info(struct addr_location *al, struct callchain_cursor_node *node,
bool hide_unresolved)
{
- struct machine *machine = maps__machine(node->ms.maps);
+ struct machine *machine = node->ms.maps ? maps__machine(node->ms.maps) : NULL;
maps__put(al->maps);
al->maps = maps__get(node->ms.maps);
--
2.43.0
