libhb_so_recv(): don't pass a NULL filter to Filter__clear.  Not sure
why thr->filter can be NULL here, though.


git-svn-id: svn://svn.valgrind.org/valgrind/trunk@11136 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/helgrind/libhb_core.c b/helgrind/libhb_core.c
index 004ce69..ce3f889 100644
--- a/helgrind/libhb_core.c
+++ b/helgrind/libhb_core.c
@@ -5711,7 +5711,8 @@
          //VtsID__rcinc(thr->viW);
       }
 
-      Filter__clear(thr->filter, "libhb_so_recv");
+      if (thr->filter)
+         Filter__clear(thr->filter, "libhb_so_recv");
       note_local_Kw_n_stack_for(thr);
 
       if (strong_recv)