fix race condition that can cause crashes at client or exit relay

Avoid crashing if the client is trying to upload many bytes and the
circuit gets torn down at the same time, or if the flip side
happens on the exit relay. Bugfix on 0.2.0.1-alpha; fixes bug 1150.

1 files changed, 2 insertions, 0 deletions

diff --git a/src/or/circuitlist.c b/src/or/circuitlist.c
index 5918bdd7ae..c55ba4dee4 100644
--- a/src/or/circuitlist.c
+++ b/src/or/circuitlist.c
@@ -1097,6 +1097,7 @@ _circuit_mark_for_close(circuit_t *circ, int reason, int line,
     edge_connection_t *conn;
     for (conn=or_circ->n_streams; conn; conn=conn->next_stream)
       connection_edge_destroy(or_circ->p_circ_id, conn);
+    or_circ->n_streams = NULL;
 
     while (or_circ->resolving_streams) {
       conn = or_circ->resolving_streams;
@@ -1120,6 +1121,7 @@ _circuit_mark_for_close(circuit_t *circ, int reason, int line,
     edge_connection_t *conn;
     for (conn=ocirc->p_streams; conn; conn=conn->next_stream)
       connection_edge_destroy(circ->n_circ_id, conn);
+    ocirc->p_streams = NULL;
   }
 
   circ->marked_for_close = line;