[PATCH v1 7/7] perf session: Check lbr_stack for NULL in callchain__lbr_callstack_printf()

[Ian Rogers]

callchain__lbr_callstack_printf() can be called on an evsel with branch
callstack enabled even if a particular sample has no branch_stack payload
(sample->branch_stack == NULL). Check that lbr_stack is non-NULL before
dereferencing lbr_stack->nr.

Fixes: febea9ec382f ("perf inject/aslr: Add ASLR tool infrastructure and MMAP tracking")
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/util/session.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index d9d06337933f..a58b4fe44b62 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1302,7 +1302,7 @@ static void callchain__lbr_callstack_printf(struct perf_sample *sample)
 			break;
 	}
 
-	if ((i != kernel_callchain_nr) && lbr_stack->nr) {
+	if ((i != kernel_callchain_nr) && lbr_stack && lbr_stack->nr) {
 		u64 total_nr;
 		/*
 		 * LBR callstack can only get user call chain,
-- 
2.56.0.307.g5fe7bd680c-goog