ast: avoid null pointer deref in ut_new_exception()

When reporting parse errors, we might not have a function context so avoid
dereferencing it without checking.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

1 files changed, 1 insertions, 1 deletions

diff --git a/ast.c b/ast.c
index 4818ee9..1a7355a 100644
--- a/ast.c
+++ b/ast.c
@@ -426,7 +426,7 @@ ut_new_exception(struct ut_state *s, uint32_t off, const char *fmt, ...)
 
 	for (callstack = &here, prevcall = NULL; callstack != NULL;
 	     prevcall = callstack, callstack = callstack->next)
-		if (callstack->off && callstack->function->source &&
+		if (callstack->off && callstack->function && callstack->function->source &&
 		    (!prevcall || callstack->function != prevcall->function || callstack->off != prevcall->off))
 			add_stacktrace(a, callstack->function, callstack->off);