rx-race-condition-cleanup-by-adding-busy-status-20010605

set a busy status on a connection to prevent it from being deleted while in use

diff --git a/src/rx/rx.c b/src/rx/rx.c
index 43fa1665cd1b6dce694cc4e0fe10ca7ecbc15ef2..8f96aa00c47433754698ba42e1cd8993254c3d9a 100644 (file)
--- a/src/rx/rx.c
+++ b/src/rx/rx.c
@@ -863,7 +863,7 @@ static void rxi_DestroyConnectionNoLock(conn)
        MUTEX_EXIT(&rx_stats_mutex);
     }
 
-    if (conn->refCount > 0) {
+    if ((conn->refCount > 0) || (conn->flags & RX_CONN_BUSY)) {
        /* Busy; wait till the last guy before proceeding */
        MUTEX_EXIT(&conn->conn_data_lock);
        USERPRI;
@@ -1763,6 +1763,7 @@ afs_int32 rx_EndCall(call, rc)
        MUTEX_ENTER(&conn->conn_call_lock);
        MUTEX_ENTER(&call->lock);
        MUTEX_ENTER(&conn->conn_data_lock);
+       conn->flags |= RX_CONN_BUSY;
        if (conn->flags & RX_CONN_MAKECALL_WAITING) {
            conn->flags &= (~RX_CONN_MAKECALL_WAITING);
            MUTEX_EXIT(&conn->conn_data_lock);
@@ -1801,8 +1802,10 @@ afs_int32 rx_EndCall(call, rc)
 
     CALL_RELE(call, RX_CALL_REFCOUNT_BEGIN);
     MUTEX_EXIT(&call->lock);
-    if (conn->type == RX_CLIENT_CONNECTION)
+    if (conn->type == RX_CLIENT_CONNECTION) {
        MUTEX_EXIT(&conn->conn_call_lock);
+       conn->flags &= ~RX_CONN_BUSY;
+    }
     AFS_RXGUNLOCK();
     USERPRI;
     /*
@@ -6600,7 +6603,8 @@ static int rxi_AddRpcStat(
      * queue.
      */
 
-    if ((rpc_stat == NULL) ||
+    if (queue_IsEnd(stats, rpc_stat) ||
+       (rpc_stat == NULL) ||
        (rpc_stat->stats[0].interfaceId != rxInterface) ||
        (rpc_stat->stats[0].remote_is_server != isServer)) {
        int i;

diff --git a/src/rx/rx.h b/src/rx/rx.h
index 7820cb0687e757c0db2dbfe31013aac34498c047..03be43d02f81460eb8cca7db33ac5b231574685d 100644 (file)
--- a/src/rx/rx.h
+++ b/src/rx/rx.h
@@ -481,6 +481,7 @@ struct rx_connection {
 #define RX_CONN_USING_PACKET_CKSUM  4  /* non-zero header.spare field seen */
 #define RX_CONN_KNOW_WINDOW         8   /* window size negotiation works */
 #define RX_CONN_RESET             16   /* connection is reset, remove */
+#define RX_CONN_BUSY               32   /* connection is busy; don't delete */
 
 /* Type of connection, client or server */
 #define        RX_CLIENT_CONNECTION    0