| Message ID | 20170802111151.1818472-1-arnd@arndb.de |
|---|---|
| State | Accepted |
| Commit | 8a5a90a2a477b86a3dc2eaa5a706db9bfdd647ca |
| Headers | show |
diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 6a8563633d4b..f8eba1c5412f 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;
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> --- drivers/tty/tty_buffer.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) -- 2.9.0