This is a note to let you know that I've just added the patch titled
vt_kdsetmode: extend console locking
to the 5.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
vt_kdsetmode-extend-console-locking.patch
and it can be found in the queue-5.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2287a51ba822384834dafc1c798453375d1107c7 Mon Sep 17 00:00:00 2001
From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Date: Mon, 30 Aug 2021 08:55:18 -0700
Subject: vt_kdsetmode: extend console locking
From: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
commit 2287a51ba822384834dafc1c798453375d1107c7 upstream.
As per the long-suffering comment.
Reported-by: Minh Yuan <yuanmingbuaa@xxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Cc: Jiri Slaby <jirislaby@xxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/tty/vt/vt_ioctl.c | 10 ++++++----
1 file changed, 6 insertions(+), 4 deletions(-)
--- a/drivers/tty/vt/vt_ioctl.c
+++ b/drivers/tty/vt/vt_ioctl.c
@@ -246,6 +246,8 @@ int vt_waitactive(int n)
*
* XXX It should at least call into the driver, fbdev's definitely need to
* restore their engine state. --BenH
+ *
+ * Called with the console lock held.
*/
static int vt_kdsetmode(struct vc_data *vc, unsigned long mode)
{
@@ -262,7 +264,6 @@ static int vt_kdsetmode(struct vc_data *
return -EINVAL;
}
- /* FIXME: this needs the console lock extending */
if (vc->vc_mode == mode)
return 0;
@@ -271,12 +272,10 @@ static int vt_kdsetmode(struct vc_data *
return 0;
/* explicitly blank/unblank the screen if switching modes */
- console_lock();
if (mode == KD_TEXT)
do_unblank_screen(1);
else
do_blank_screen(1);
- console_unlock();
return 0;
}
@@ -378,7 +377,10 @@ static int vt_k_ioctl(struct tty_struct
if (!perm)
return -EPERM;
- return vt_kdsetmode(vc, arg);
+ console_lock();
+ ret = vt_kdsetmode(vc, arg);
+ console_unlock();
+ return ret;
case KDGETMODE:
return put_user(vc->vc_mode, (int __user *)arg);
Patches currently in stable-queue which might be from torvalds@xxxxxxxxxxxxxxxxxxxx are
queue-5.14/vt_kdsetmode-extend-console-locking.patch
