From: Jiri Slaby <jslaby@suse.cz> stable inclusion from stable-v4.19.254 commit f8b10bd4d2a95268490c86a6ddac8d5eb7955150 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5A5Y1 CVE: CVE-2022-1462 -------------------------------- commit 716b10580283fda66f2b88140e3964f8a7f9da89 upstream. We will need this new helper in the next patch. Cc: Hillf Danton <hdanton@sina.com> Cc: 一只狗 <chennbnbnb@gmail.com> Cc: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20220707082558.9250-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Yi Yang <yiyang13@huawei.com> Reviewed-by: Xiu Jianfeng <xiujianfeng@huawei.com> Reviewed-by: Wang Weiyang <wangweiyang2@huawei.com> Signed-off-by: Yongqiang Liu <liuyongqiang13@huawei.com> --- drivers/tty/tty_buffer.c | 15 ++++++++++----- 1 file changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/tty/tty_buffer.c b/drivers/tty/tty_buffer.c index 8728342c6482..31b158019c1a 100644 --- a/drivers/tty/tty_buffer.c +++ b/drivers/tty/tty_buffer.c @@ -519,6 +519,15 @@ static void flush_to_ldisc(struct work_struct *work) } +static inline void tty_flip_buffer_commit(struct tty_buffer *tail) +{ + /* + * Paired w/ acquire in flush_to_ldisc(); ensures flush_to_ldisc() sees + * buffer data. + */ + smp_store_release(&tail->commit, tail->used); +} + /** * tty_flip_buffer_push - terminal * @port: tty port to push @@ -534,11 +543,7 @@ void tty_flip_buffer_push(struct tty_port *port) { struct tty_bufhead *buf = &port->buf; - /* - * Paired w/ acquire in flush_to_ldisc(); ensures flush_to_ldisc() sees - * buffer data. - */ - smp_store_release(&buf->tail->commit, buf->tail->used); + tty_flip_buffer_commit(buf->tail); queue_work(system_unbound_wq, &buf->work); } EXPORT_SYMBOL(tty_flip_buffer_push); -- 2.25.1