[PATCH 5.14 01/11] vt_kdsetmode: extend console locking
From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Date: 2021-09-01 12:55:36
Also in:
lkml
From: Linus Torvalds <torvalds@linux-foundation.org> commit 2287a51ba822384834dafc1c798453375d1107c7 upstream. As per the long-suffering comment. Reported-by: Minh Yuan <redacted> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jirislaby@kernel.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- 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);