diff options
| author | Arnd Bergmann <arnd@arndb.de> | 2017-08-02 13:11:39 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-09-24 22:29:14 +0200 |
| commit | 928144cbe9ef625a462482cc5422091837d236c9 (patch) | |
| tree | f6061a7337be119f19de2d06b24c82d4cf62d4a9 | |
| parent | 2dab53725f0adf22e54b10491bcdbe5f22ff9a76 (diff) | |
tty: fix __tty_insert_flip_char regression
commit 8a5a90a2a477b86a3dc2eaa5a706db9bfdd647ca upstream.
Sergey noticed a small but fatal mistake in __tty_insert_flip_char,
leading to an oops in an interrupt handler when using any serial
port.
The problem is that I accidentally took the tty_buffer pointer
before calling __tty_buffer_request_room(), which replaces the
buffer. This moves the pointer lookup to the right place after
allocating the new buffer space.
Fixes: 979990c62848 ("tty: improve tty_insert_flip_char() fast path")
Reported-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Tested-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/tty/tty_buffer.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index e4d0ef844d9d..8f3566cde3eb 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -372,12 +372,13 @@ EXPORT_SYMBOL(tty_insert_flip_string_flags); */ int __tty_insert_flip_char(struct tty_port *port, unsigned char ch, char flag) { - struct tty_buffer *tb = port->buf.tail; + struct tty_buffer *tb; int flags = (flag == TTY_NORMAL) ? TTYB_NORMAL : 0; if (!__tty_buffer_request_room(port, 1, flags)) return 0; + tb = port->buf.tail; if (~tb->flags & TTYB_NORMAL) *flag_buf_ptr(tb, tb->used) = flag; *char_buf_ptr(tb, tb->used++) = ch; |