Merging upstream version 6.1.85.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 12 insertions, 5 deletions

diff --git a/fs/pipe.c b/fs/pipe.c
index 9873a6030..aa8e6ffe1 100644
--- a/fs/pipe.c
+++ b/fs/pipe.c
@@ -424,6 +424,18 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
 	bool was_empty = false;
 	bool wake_next_writer = false;
 
+	/*
+	 * Reject writing to watch queue pipes before the point where we lock
+	 * the pipe.
+	 * Otherwise, lockdep would be unhappy if the caller already has another
+	 * pipe locked.
+	 * If we had to support locking a normal pipe and a notification pipe at
+	 * the same time, we could set up lockdep annotations for that, but
+	 * since we don't actually need that, it's simpler to just bail here.
+	 */
+	if (pipe_has_watch_queue(pipe))
+		return -EXDEV;
+
 	/* Null write succeeds. */
 	if (unlikely(total_len == 0))
 		return 0;
@@ -436,11 +448,6 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from)
 		goto out;
 	}
 
-	if (pipe_has_watch_queue(pipe)) {
-		ret = -EXDEV;
-		goto out;
-	}
-
 	/*
 	 * If it wasn't empty we try to merge new data into
 	 * the last buffer.