avfilter/vsrc_mandelbrot: Check for malloc failure

Reviewed-by: Paul B Mahol <onemda@gmail.com>
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>

libavfilter/vsrc_mandelbrot.c

@@ -134,6 +134,9 @@ static av_cold int init(AVFilterContext *ctx)
     s-> next_cache= av_malloc_array(s->cache_allocated, sizeof(*s-> next_cache));
     s-> zyklus    = av_malloc_array(s->maxiter + 16, sizeof(*s->zyklus));
 
+    if (!s->point_cache || !s->next_cache || !s->zyklus)
+        return AVERROR(ENOMEM);
+
     return 0;
 }