SUNRPC: Fix a potential race in rpc_execute

If the rpc_task is asynchronous, it could theoretically finish executing
on the workqueue it was assigned by rpc_make_runnable() before we get
round to testing RPC_IS_ASYNC() in rpc_execute.

In practice, however, all the existing callers hold a reference to the
rpc_task, so this can't happen today...

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 5356b120dbf8e2fe61ba88081d1fab1941f135a9..849ca413522c415104971e7bcf1dea36a951b0b5 100644 (file)
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -825,9 +825,11 @@ static void __rpc_execute(struct rpc_task *task)
  */
 void rpc_execute(struct rpc_task *task)
 {
+       bool is_async = RPC_IS_ASYNC(task);
+
        rpc_set_active(task);
        rpc_make_runnable(task);
-       if (!RPC_IS_ASYNC(task))
+       if (!is_async)
                __rpc_execute(task);
 }