[PATCH] bcachefs: return the error code instead of the return value of IS_ERR_OR_NULL

[Edward Adam Davis]

Syzbot report a kernel BUG in vfs_get_tree.
The root cause is that read_btree_nodes() returned 1 and returned -EINTR
due to kthread_run() execution failure.

The -EINTR needs to be returnned to bch2_fs_recovery(), not return to
"ret = IS_ERR_OR_NULL(t)".

Reported-and-tested-by: syzbot+c0360e8367d6d8d04a66@xxxxxxxxxxxxxxxxxxxxxxxxx
Closes: https://syzkaller.appspot.com/bug?extid=c0360e8367d6d8d04a66
Signed-off-by: Edward Adam Davis <eadavis@xxxxxx>
---
 fs/bcachefs/btree_node_scan.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/bcachefs/btree_node_scan.c b/fs/bcachefs/btree_node_scan.c
index b28c649c6838..df7090ca1e81 100644
--- a/fs/bcachefs/btree_node_scan.c
+++ b/fs/bcachefs/btree_node_scan.c
@@ -281,6 +281,10 @@ static int read_btree_nodes(struct find_btree_nodes *f)
 			closure_put(&cl);
 			f->ret = ret;
 			bch_err(c, "error starting kthread: %i", ret);
+			if (IS_ERR(t)) {
+				closure_sync(&cl);
+				return PTR_ERR(t);
+			}
 			break;
 		}
 	}
-- 
2.43.0