SUNRPC: Ensure we always run the tk_callback before tk_action

This fixes a race in which the task->tk_callback() puts the rpc_task
to sleep, setting a new callback. Under certain circumstances, the current
code may end up executing the task->tk_action before it gets round to the
callback.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: stable@kernel.org

1 files changed, 6 insertions, 8 deletions

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index 5681c6a12d20..2e9387b23841 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -630,14 +630,12 @@ static void __rpc_execute(struct rpc_task *task)
                         save_callback = task->tk_callback;
                         task->tk_callback = NULL;
                         save_callback(task);
-                }
-
-                /*
-                 * Perform the next FSM step.
-                 * tk_action may be NULL when the task has been killed
-                 * by someone else.
-                 */
-                if (!RPC_IS_QUEUED(task)) {
+                } else {
+                        /*
+                         * Perform the next FSM step.
+                         * tk_action may be NULL when the task has been killed
+                         * by someone else.
+                         */
                         if (task->tk_action == NULL)
                                 break;
                         task->tk_action(task);