This is a note to let you know that I've just added the patch titled vt_kdsetmode: extend console locking to the 5.10-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-5.10 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-5.10/pipe-do-fasync-notifications-for-every-pipe-io-not-just-state-changes.patch queue-5.10/pipe-avoid-unnecessary-epollet-wakeups-under-normal-loads.patch queue-5.10/vt_kdsetmode-extend-console-locking.patch