NFS Client Bugfixes for Linux 6.4-rc

Stable Fix:
   * Don't change task->tk_status after the call to rpc_exit_task
 
 Other Bugfixes:
   * Convert kmap_atomic() to kmap_local_folio()
   * Fix a potential double free with READ_PLUS
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Merge tag 'nfs-for-6.4-2' of git://git.linux-nfs.org/projects/anna/linux-nfs

Pull NFS client fixes from Anna Schumaker:
 "Stable Fix:

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

  Other Bugfixes:

   - Convert kmap_atomic() to kmap_local_folio()

   - Fix a potential double free with READ_PLUS"

* tag 'nfs-for-6.4-2' of git://git.linux-nfs.org/projects/anna/linux-nfs:
  NFSv4.2: Fix a potential double free with READ_PLUS
  SUNRPC: Don't change task->tk_status after the call to rpc_exit_task
  NFS: Convert kmap_atomic() to kmap_local_folio()

fs/nfs/dir.c

@@ -317,7 +317,7 @@ static int nfs_readdir_folio_array_append(struct folio *folio,
 
 	name = nfs_readdir_copy_name(entry->name, entry->len);
 
-	array = kmap_atomic(folio_page(folio, 0));
+	array = kmap_local_folio(folio, 0);
 	if (!name)
 		goto out;
 	ret = nfs_readdir_array_can_expand(array);
@@ -340,7 +340,7 @@ static int nfs_readdir_folio_array_append(struct folio *folio,
 		nfs_readdir_array_set_eof(array);
 out:
 	*cookie = array->last_cookie;
-	kunmap_atomic(array);
+	kunmap_local(array);
 	return ret;
 }
 

fs/nfs/nfs4proc.c

@@ -5437,10 +5437,18 @@ static bool nfs4_read_plus_not_supported(struct rpc_task *task,
 	return false;
 }
 
+static inline void nfs4_read_plus_scratch_free(struct nfs_pgio_header *hdr)
+{
+	if (hdr->res.scratch) {
+		kfree(hdr->res.scratch);
+		hdr->res.scratch = NULL;
+	}
+}
+
 static int nfs4_read_done(struct rpc_task *task, struct nfs_pgio_header *hdr)
 {
-	if (hdr->res.scratch)
-		kfree(hdr->res.scratch);
+	nfs4_read_plus_scratch_free(hdr);
+
 	if (!nfs4_sequence_done(task, &hdr->res.seq_res))
 		return -EAGAIN;
 	if (nfs4_read_stateid_changed(task, &hdr->args))

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) {