perf dso: Fix use before NULL check introduced by map__dso() introduction

James Clark noticed that the recent 63df0e4bc368adbd ("perf map: Add
accessor for dso") patch accessed map->dso before the 'map' variable was
NULL checked, which is a change in logic that leads to segmentation
faults, so comb thru that patch to fix similar cases.

Fixes: 63df0e4bc368adbd ("perf map: Add accessor for dso")
Acked-by: Ian Rogers <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: James Clark <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: John Garry <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Mathieu Poirier <[email protected]>
Cc: Mike Leach <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Peter Zijlstra <[email protected]
Cc: Suzuki Poulouse <[email protected]>
Cc: Will Deacon <[email protected]>
Link: https://lore.kernel.org/lkml/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

1 files changed, 3 insertions, 4 deletions

diff --git a/tools/perf/builtin-script.c b/tools/perf/builtin-script.c
index 8fba247b798c..006f522d0e7f 100644
--- a/tools/perf/builtin-script.c
+++ b/tools/perf/builtin-script.c
@@ -1075,8 +1075,7 @@ static int grab_bb(u8 *buffer, u64 start, u64 end,
 		return 0;
 	}
 
-	dso = map__dso(al.map);
-	if (!thread__find_map(thread, *cpumode, start, &al) || !dso) {
+	if (!thread__find_map(thread, *cpumode, start, &al) || (dso = map__dso(al.map)) == NULL) {
 		pr_debug("\tcannot resolve %" PRIx64 "-%" PRIx64 "\n", start, end);
 		return 0;
 	}
@@ -1106,9 +1105,9 @@ static int map__fprintf_srccode(struct map *map, u64 addr, FILE *fp, struct srcc
 	unsigned line;
 	int len;
 	char *srccode;
-	struct dso *dso = map__dso(map);
+	struct dso *dso;
 
-	if (!map || !dso)
+	if (!map || (dso = map__dso(map)) == NULL)
 		return 0;
 	srcfile = get_srcline_split(dso,
 				    map__rip_2objdump(map, addr),