linux.git/drivers/tty/vt/vt.c, branch v5.6

vt: selection, push console lock down

2020-02-28T15:06:49+00:00

We need to nest the console lock in sel_lock, so we have to push it down
a bit. Fortunately, the callers of set_selection_* just lock the console
lock around the function call. So moving it down is easy.

In the next patch, we switch the order.

Signed-off-by: Jiri Slaby 
Fixes: 07e6124a1a46 ("vt: selection, close sel_buffer race")
Cc: stable 
Link: https://lore.kernel.org/r/20200228115406.5735-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman

vt: fix scrollback flushing on background consoles

2020-02-10T21:51:44+00:00

Commit a6dbe4427559 ("vt: perform safe console erase in the right
order") provided fixes to an earlier commit by gathering all console
scrollback flushing operations in a function of its own. This includes
the invocation of vc_sw->con_switch() as previously done through a
update_screen() call. That commit failed to carry over the
con_is_visible() conditional though, as well as cursor handling, which
caused problems when "\e[3J" was written to a background console.

One could argue for preserving the call to update_screen(). However
this does far more than we need, and it is best to remove scrollback
assumptions from it. Instead let's gather the minimum needed to actually
perform scrollback flushing properly in that one place.

While at it, let's document the vc_sw->con_switch() side effect being
relied upon.

Signed-off-by: Nicolas Pitre 
Reported-and-tested-by: Lukas Wunner 
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.2001281205560.1655@knanqh.ubzr
Signed-off-by: Greg Kroah-Hartman

vt: Correct comment documenting do_take_over_console()

2020-01-14T15:00:54+00:00

Commit 3e795de7631b ("[PATCH] VT binding: Add binding/unbinding support
for the VT console") introduced a code comment claiming that
"do_take_over_console is basically a register followed by unbind".

However the function actually performs a register followed by *bind*.

Signed-off-by: Lukas Wunner 
Cc: Antonino A. Daplas 
Link: https://lore.kernel.org/r/a500f005ba7013ca8165a6d42f59b2183d56114f.1578574427.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman

vt: Delete comment referencing non-existent unbind_con_driver()

2020-01-14T15:00:54+00:00

Commit c1f5e38a5d35 ("vt: delete unneeded function unbind_con_driver")
removed unbind_con_driver() but retained a comment referencing the
function.  Delete it.

Signed-off-by: Lukas Wunner 
Cc: Wang YanQing 
Link: https://lore.kernel.org/r/4d77a67d77a1c699e9a6cc3e73044c31c02d60b5.1578574427.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman

vt: Initialize conswitchp to dummy_con if unset

2020-01-14T14:29:15+00:00

If the arch setup code hasn't initialized conswitchp yet, set it to
dummy_con in con_init. This will allow us to drop the dummy_con
initialization that's done in almost every architecture.

Signed-off-by: Arvind Sankar 
Link: https://lore.kernel.org/r/20191218214506.49252-3-nivedita@alum.mit.edu
Signed-off-by: Greg Kroah-Hartman

vt: Grab console_lock around con_is_bound in show_bind

2019-07-25T11:47:35+00:00

Not really harmful not to, but also not harm in grabbing the lock. And
this shuts up a new WARNING I introduced in commit ddde3c18b700 ("vt:
More locking checks").

Reported-by: Jens Remus 
Cc: linux-kernel@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: Nicolas Pitre 
Cc: Martin Hostettler 
Cc: Adam Borowski 
Cc: Mikulas Patocka 
Cc: Daniel Vetter 
Cc: Sam Ravnborg 
Fixes: ddde3c18b700 ("vt: More locking checks")
Signed-off-by: Daniel Vetter 
Tested-by: Jens Remus 
Acked-by: Sam Ravnborg 
Link: https://lore.kernel.org/r/20190718080903.22622-1-daniel.vetter@ffwll.ch
Signed-off-by: Greg Kroah-Hartman

vt: More locking checks

2019-06-12T18:27:13+00:00

I honestly have no idea what the subtle differences between
con_is_visible, con_is_fg (internal to vt.c) and con_is_bound are. But
it looks like both vc->vc_display_fg and con_driver_map are protected
by the console_lock, so probably better if we hold that when checking
this.

To do that I had to deinline the con_is_visible function.

Signed-off-by: Daniel Vetter 
Reviewed-by: Sam Ravnborg 
Acked-by: Greg Kroah-Hartman 
Reviewed-by: Maarten Lankhorst 
Cc: Greg Kroah-Hartman 
Cc: Nicolas Pitre 
Cc: Martin Hostettler 
Cc: Adam Borowski 
Cc: Daniel Vetter 
Cc: Mikulas Patocka 
Link: https://patchwork.freedesktop.org/patch/msgid/20190528090304.9388-5-daniel.vetter@ffwll.ch

vt: might_sleep() annotation for do_blank_screen

2019-06-12T18:27:07+00:00

For symmetry reasons with do_unblank_screen, except without the
oops_in_progress special case.

Just a drive-by annotation while I'm trying to untangle the fbcon vs.
fbdev screen blank/unblank maze.

Signed-off-by: Daniel Vetter 
Reviewed-by: Sam Ravnborg 
Acked-by: Greg Kroah-Hartman 
Reviewed-by: Maarten Lankhorst 
Cc: Greg Kroah-Hartman 
Cc: Nicolas Pitre 
Cc: Adam Borowski 
Cc: Martin Hostettler 
Cc: Daniel Vetter 
Cc: Mikulas Patocka 
Link: https://patchwork.freedesktop.org/patch/msgid/20190528090304.9388-4-daniel.vetter@ffwll.ch

vt/fbcon: deinitialize resources in visual_init() after failed memory allocation

2019-05-24T15:08:18+00:00

After memory allocation failure vc_allocate() doesn't clean up data
which has been initialized in visual_init(). In case of fbcon this
leads to divide-by-0 in fbcon_init() on next open of the same tty.

memory allocation in vc_allocate() may fail here:
1097:     vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_KERNEL);

on next open() fbcon_init() skips vc_font.data initialization:
1088:     if (!p->fontdata) {

division by zero in fbcon_init() happens here:
1149:     new_cols /= vc->vc_font.width;

Additional check is needed in fbcon_deinit() to prevent
usage of uninitialized vc_screenbuf:

1251:        if (vc->vc_hi_font_mask && vc->vc_screenbuf)
1252:                set_vc_hi_font(vc, false);

Crash:

 #6 [ffffc90001eafa60] divide_error at ffffffff81a00be4
    [exception RIP: fbcon_init+463]
    RIP: ffffffff814b860f  RSP: ffffc90001eafb18  RFLAGS: 00010246
...
 #7 [ffffc90001eafb60] visual_init at ffffffff8154c36e
 #8 [ffffc90001eafb80] vc_allocate at ffffffff8154f53c
 #9 [ffffc90001eafbc8] con_install at ffffffff8154f624
...

Signed-off-by: Grzegorz Halat 
Reviewed-by: Oleksandr Natalenko 
Acked-by: Bartlomiej Zolnierkiewicz 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

Merge tag 'tty-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2019-05-08T17:07:28+00:00

Pull tty/serial updates from Greg KH:
 "Here is the "big" set of tty/serial driver patches for 5.2-rc1.

  It's really pretty small, not much happening in this portion of the
  kernel at the moment. When the "highlight" is the movement of the
  documentation from .txt to .rst files, it's a good merge window.

  There's a number of small fixes and updates over the various serial
  drivers, and a new "tty null" driver for those embedded systems that
  like to make things even smaller and not break things.

  All of these have been in linux-next for a while with no reported
  issues"

* tag 'tty-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (45 commits)
  tty: serial: add driver for the SiFive UART
  dt-bindings: serial: add documentation for the SiFive UART driver
  serial: uartps: Add support for cts-override
  dt-bindings: xilinx-uartps: Add support for cts-override
  serial: milbeaut_usio: Fix error handling in probe and remove
  tty: rocket: deprecate the rp_ioctl
  tty: rocket: Remove RCPK_GET_STRUCT ioctl
  tty: update obsolete termios comment
  tty: serial_core: fix error code returned by uart_register_driver()
  serial: 8250-mtk: modify baudrate setting
  serial: 8250-mtk: add follow control
  docs: serial: convert docs to ReST and rename to *.rst
  serial: 8250_exar: Adjust IOT2000 matching
  TTY: serial_core, add ->install
  serial: Fix using plain integer instead of Null pointer
  tty:serial_core: Spelling mistake
  tty: Add NULL TTY driver
  tty: vt: keyboard: Allow Unicode compose base char
  Revert "tty: fix NULL pointer issue when tty_port ops is not set"
  serial: Add Milbeaut serial control
  ...