tty: Ensure single-threaded flip buffer consumer with mutex
The buffer work may race with parallel tty_buffer_flush. Use a
mutex to guarantee exclusive modify access to the head flip
buffer.
Remove the unneeded spin lock.
Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/include/linux/tty.h b/include/linux/tty.h
index 7c12454..1c8fef0 100644
--- a/include/linux/tty.h
+++ b/include/linux/tty.h
@@ -66,7 +66,7 @@
struct tty_bufhead {
struct work_struct work;
- spinlock_t lock;
+ struct mutex flush_mutex;
struct tty_buffer sentinel;
struct tty_buffer *head; /* Queue head */
struct tty_buffer *tail; /* Active buffer */