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authorArnd Bergmann <arnd@arndb.de>2017-08-02 11:11:39 (GMT)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-09-27 12:39:19 (GMT)
commit346abf2aca7faeea9f7d615239e94b37b0ee6df2 (patch)
tree1ee3aaaff7438955e3dc1c53291903d6c43e594f /drivers/tty
parent750462424193bfa48155c26e0186f2bb5a4485e2 (diff)
downloadlinux-346abf2aca7faeea9f7d615239e94b37b0ee6df2.tar.xz
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>
Diffstat (limited to 'drivers/tty')
-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 6b1dc32..c220c2c 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;