perf script report: Fix SEGFAULT when using DWARF mode

When running perf script report with a Python script and a callgraph in
DWARF mode, intr_regs->regs can be 0 and therefore crashing the regs_map
function.

Added a check for this condition (same check as in builtin-script.c:595).

Signed-off-by: Andreas Gerstmayr <agerstmayr@redhat.com>
Tested-by: Kim Phillips <kim.phillips@amd.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Link: http://lore.kernel.org/lkml/20200402125417.422232-1-agerstmayr@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c
index 8c1b27cd8b99235035f8a9e3b4b50fdecefe524a..2c372cf5495e5537c6948ff62f87b12313e91a61 100644 (file)
--- a/tools/perf/util/scripting-engines/trace-event-python.c
+++ b/tools/perf/util/scripting-engines/trace-event-python.c
@@ -694,6 +694,9 @@ static int regs_map(struct regs_dump *regs, uint64_t mask, char *bf, int size)
 
        bf[0] = 0;
 
+       if (!regs || !regs->regs)
+               return 0;
+
        for_each_set_bit(r, (unsigned long *) &mask, sizeof(mask) * 8) {
                u64 val = regs->regs[i++];