watch_queue: Fix to release page in ->release()

When a pipe ring descriptor points to a notification message, the
refcount on the backing page is incremented by the generic get function,
but the release function, which marks the bitmap, doesn't drop the page
ref.

Fix this by calling generic_pipe_buf_release() at the end of
watch_queue_pipe_buf_release().

Fixes: c73be61ced ("pipe: Add general notification queue support")
Reported-by: Jann Horn <jannh@google.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
David Howells 2022-03-11 13:23:46 +00:00 committed by Linus Torvalds
parent db8facfc9f
commit c1853fbadc

View File

@ -54,6 +54,7 @@ static void watch_queue_pipe_buf_release(struct pipe_inode_info *pipe,
bit += page->index;
set_bit(bit, wqueue->notes_bitmap);
generic_pipe_buf_release(pipe, buf);
}
// No try_steal function => no stealing