NFS: Fix a use-after-free case in nfs_async_rename()

The call to nfs_async_rename_release() after rpc_run_task() is incorrect.
The rpc_run_task() is always guaranteed to call the ->rpc_release() method.

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

1 files changed, 2 insertions, 7 deletions

diff --git a/fs/nfs/unlink.c b/fs/nfs/unlink.c
index 698b3e6367ff..47530aacebfd 100644
--- a/fs/nfs/unlink.c
+++ b/fs/nfs/unlink.c
@@ -426,7 +426,6 @@ nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
                 .rpc_client = NFS_CLIENT(old_dir),
                 .flags = RPC_TASK_ASYNC,
         };
-        struct rpc_task *task;
 
         data = kmalloc(sizeof(*data), GFP_KERNEL);
         if (data == NULL)
@@ -435,7 +434,7 @@ nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
 
         data->cred = rpc_lookup_cred();
         if (IS_ERR(data->cred)) {
-                task = (struct rpc_task *)data->cred;
+                struct rpc_task *task = ERR_CAST(data->cred);
                 kfree(data);
                 return task;
         }
@@ -468,11 +467,7 @@ nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
 
         NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dir);
 
-        task = rpc_run_task(&task_setup_data);
-        if (IS_ERR(task))
-                nfs_async_rename_release(data);
-
-        return task;
+        return rpc_run_task(&task_setup_data);
 }
 
 /**