linux.git/drivers/tty/vt, branch v6.19

tty: vt: do not open code DIV_ROUND_UP()

2025-11-21T17:31:27+00:00

Use the designated DIV_ROUND_UP() macro instead of explicit addition
with division.

Signed-off-by: Jiri Slaby (SUSE) 
Link: https://patch.msgid.link/20251119092457.826789-2-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: vt/keyboard: use guard()s

2025-11-21T17:30:40+00:00

Use guards in the vt/keyboard code. This improves readability, makes
error handling easier, and marks locked portions of code explicit. All
that while being sure the lock is unlocked.

Signed-off-by: Jiri Slaby (SUSE) 
Link: https://patch.msgid.link/20251119100140.830761-9-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: vt/keyboard: simplify returns from vt_do_kbkeycode_ioctl()

2025-11-21T17:30:40+00:00

Return immediately when something goes wrong in vt_do_kbkeycode_ioctl().
This makes the code flow more obvious.

Signed-off-by: Jiri Slaby (SUSE) 
Link: https://patch.msgid.link/20251119100140.830761-8-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

tty: vt/keyboard: use __free()

2025-11-21T17:30:40+00:00

The vt/keyboard code can use __free to ensure the temporary buffers are
freed. Perform the switch.

And even one non-temporary in kbd_connect(). There are fail paths, so
ensure the buffer is freed in them and not when returning 0 -- by
retain_and_null_ptr().

Signed-off-by: Jiri Slaby (SUSE) 
Link: https://patch.msgid.link/20251119100140.830761-7-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman

drivers/tty/vt: use umin() instead of min_t(u16, ...) for row/col limits

2025-11-21T17:16:11+00:00

The row/column bounds (for a screen window box) are changed from
'offset one' to 'offset zero' and bound to the screen size using:
	v->xs = min_t(u16, v->xs - 1, vc->vc_cols - 1);
This has the side effect of converting zero to the limit.

A check I'm adding to min_t() reports that (u16)(v->xs - 1) (etc)
discards signiticant bits (because v->xs is promoted to 'int' before
the addition).
If v->xs is zero (it comes from userspace) it converts -1 to 0xffff.
This is then bounded to 'vc->vc_cols - 1' which will be fine.

Replace with:
	v->xs = umin(v->xs - 1, vc->vc_cols - 1);
which again converts a -1 to unsigned - this time to 0xffffffff,
with the same overall effect.

Whether zero is meant to mean the 'maximum size' is unknown.
I can't find any documentation for the ioctl and it pre-dates git.

Detected by an extra check added to min_t().

Signed-off-by: David Laight 
Reviewed-by: Jiri Slaby 
Link: https://patch.msgid.link/20251119224140.8616-28-david.laight.linux@gmail.com
Signed-off-by: Greg Kroah-Hartman

vt: move vc_saved_screen to within tty allocated judgment

2025-09-12T13:58:41+00:00

Everything starts with the assumption that a tty has been allocated.
Therefore, Move it to within the tty allocation check.

Fixes: 23743ba64709 ("vt: add support for smput/rmput escape codes")
Reported-by: syzbot+f6cb41c144427dc0796a@syzkaller.appspotmail.com
Closes: https://syzkaller.appspot.com/bug?extid=f6cb41c144427dc0796a
Tested-by: syzbot+f6cb41c144427dc0796a@syzkaller.appspotmail.com
Signed-off-by: Edward Adam Davis 
Reviewed-by: Jiri Slaby 
Link: https://lore.kernel.org/r/tencent_CAD45DB31906CF890DBB25AB0DED12205D07@qq.com
Signed-off-by: Greg Kroah-Hartman

tty/vt: Add missing return value for VT_RESIZE in vt_ioctl()

2025-09-06T13:49:55+00:00

In vt_ioctl(), the handler for VT_RESIZE always returns 0, which prevents
users from detecting errors. Add the missing return value so that errors
can be properly reported to users like vt_resizex().

Signed-off-by: Zizhi Wo 
Link: https://lore.kernel.org/r/20250904023955.3892120-1-wozizhi@huaweicloud.com
Signed-off-by: Greg Kroah-Hartman

vt: remove redundant check on vc_mode in con_font_set()

2025-09-06T13:49:52+00:00

Previous commit edab558feba1 ("vt: sort out locking for font handling")
move the vc_mode check into console_lock protect, but forget to remove the
old check in con_font_set(). Just remove the redundant check.

Signed-off-by: Wang Liang 
Link: https://lore.kernel.org/r/20250904023345.13731-1-wangliang74@huawei.com
Signed-off-by: Greg Kroah-Hartman

vt: add support for smput/rmput escape codes

2025-09-06T13:48:32+00:00

Support "\e[?1049h" and "\e[?1049l" escape codes.
This patch allows programs to enter and leave alternate screens.
This feature is widely available in graphical terminal emulators and mostly
used by fullscreen terminal-based user interfaces such as text editors.
Most editors such as vim and nano assume this escape code in not supported
and will not try to print the escape sequence if TERM=linux.
To try out this patch, run `TERM=xterm-256color vim` inside a VT.

Signed-off-by: Calixte Pernot 
Link: https://lore.kernel.org/r/20250825125607.2478-3-calixte.pernot@grenoble-inp.org
Signed-off-by: Greg Kroah-Hartman

tty/vt: use guard()s

2025-08-17T10:46:26+00:00

Having all the new guards, use them in the vt code. This improves
readability, makes error handling easier, and marks locked portions of
code explicit.

A local free_page_ptr __free guard is introduced for
__get_free_page/free_page (with proper casts). This could be made public
in include/. But I am not sure if there are more possible users, so
keeping completely private here.

Signed-off-by: "Jiri Slaby (SUSE)" 
Link: https://lore.kernel.org/r/20250814072456.182853-16-jirislaby@kernel.org
Signed-off-by: Greg Kroah-Hartman