UPSTREAM: lib/iov_iter: initialize "flags" in new pipe_buffer

commit 9d2231c5d74e13b2a0546fee6737ee4446017903 upstream.

The functions copy_page_to_iter_pipe() and push_pipe() can both
allocate a new pipe_buffer, but the "flags" member initializer is
missing.

Fixes: 241699cd72a8 ("new iov_iter flavour: pipe-backed")
To: Alexander Viro <viro@zeniv.linux.org.uk>
To: linux-fsdevel@vger.kernel.org
To: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org
Signed-off-by: Max Kellermann <max.kellermann@ionos.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
(cherry picked from commit b19ec7afa9297d862ed86443e0164643b97250ab)
Bug: 220741611
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I91076a0b6327ee8dd87e75fc875062b6adf2de4c
diff --git a/lib/iov_iter.c b/lib/iov_iter.c
index b364231..1b0a349 100644
--- a/lib/iov_iter.c
+++ b/lib/iov_iter.c
@@ -407,6 +407,7 @@
 		return 0;
 
 	buf->ops = &page_cache_pipe_buf_ops;
+	buf->flags = 0;
 	get_page(page);
 	buf->page = page;
 	buf->offset = offset;
@@ -543,6 +544,7 @@
 			break;
 
 		buf->ops = &default_pipe_buf_ops;
+		buf->flags = 0;
 		buf->page = page;
 		buf->offset = 0;
 		buf->len = min_t(ssize_t, left, PAGE_SIZE);