SUNRPC: Don't change task->tk_status after the call to rpc_exit_task

Some calls to rpc_exit_task() may deliberately change the value of
task->tk_status, for instance because it gets checked by the RPC call's
rpc_release() callback. That makes it wrong to reset the value to
task->tk_rpc_status.
In particular this causes a bug where the rpc_call_done() callback tries
to fail over a set of pNFS/flexfiles writes to a different IP address,
but the reset of task->tk_status causes nfs_commit_release_pages() to
immediately mark the file as having a fatal error.

Fixes: 39494194f93b ("SUNRPC: Fix races with rpc_killall_tasks()")
Cc: stable@vger.kernel.org # 6.1.x
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index c8321de341eea31430f3ae74cabe21ffe6564f19..6debf4fd42d4e8566f9c21f74cac24269fab012a 100644 (file)
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -927,11 +927,10 @@ static void __rpc_execute(struct rpc_task *task)
                 */
                do_action = task->tk_action;
                /* Tasks with an RPC error status should exit */
-               if (do_action != rpc_exit_task &&
+               if (do_action && do_action != rpc_exit_task &&
                    (status = READ_ONCE(task->tk_rpc_status)) != 0) {
                        task->tk_status = status;
-                       if (do_action != NULL)
-                               do_action = rpc_exit_task;
+                       do_action = rpc_exit_task;
                }
                /* Callbacks override all actions */
                if (task->tk_callback) {