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authorArnd Bergmann <arnd@arndb.de>2017-08-02 13:11:39 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-08-02 06:58:17 -0700
commit8a5a90a2a477b86a3dc2eaa5a706db9bfdd647ca (patch)
tree8b0cb50ed5818bc923d48c71b916c9c81ce8281f /drivers/tty/tty_buffer.c
parent065ea0a7afd64d6cf3464bdd1d8cd227527e2045 (diff)
downloadlinux-8a5a90a2a477b86a3dc2eaa5a706db9bfdd647ca.tar.bz2
tty: fix __tty_insert_flip_char regression
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>
Diffstat (limited to 'drivers/tty/tty_buffer.c')
-rw-r--r--drivers/tty/tty_buffer.c3
1 files changed, 2 insertions, 1 deletions
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;