kernel/linux.git/drivers/tty/vt/vt.c, branch v6.1.168

vt: add missing notification when switching back to text mode

2025-07-17T16:32:14+00:00

[ Upstream commit ff78538e07fa284ce08cbbcb0730daa91ed16722 ] Programs using poll() on /dev/vcsa to be notified when VT changes occur were missing one case: the switch from gfx to text mode. Signed-off-by: Nicolas Pitre Link: https://lore.kernel.org/r/9o5ro928-0pp4-05rq-70p4-ro385n21n723@onlyvoer.pbz Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

tty: vt: make consw::con_switch() return a bool

2025-07-06T08:57:59+00:00

[ Upstream commit 8d5cc8eed738e3202379722295c626cba0849785 ] The non-zero (true) return value from consw::con_switch() means a redraw is needed. So make this return type a bool explicitly instead of int. The latter might imply that -Eerrors are expected. They are not. And document the hook. Signed-off-by: "Jiri Slaby (SUSE)" Cc: Helge Deller Cc: "James E.J. Bottomley" Cc: Daniel Vetter Cc: linux-fbdev@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linux-parisc@vger.kernel.org Tested-by: Helge Deller # parisc STI console Link: https://lore.kernel.org/r/20240122110401.7289-31-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 03bcbbb3995b ("dummycon: Trigger redraw when switching consoles with deferred takeover") Signed-off-by: Sasha Levin

tty: vt: sanitize arguments of consw::con_clear()

2025-07-06T08:57:59+00:00

[ Upstream commit 559f01a0ee6d924c6fec3eaf6a5b078b15e71070 ] In consw::con_clear(): * Height is always 1, so drop it. * Offsets and width are always unsigned values, so re-type them as such. This needs a new __fbcon_clear() in the fbcon code to still handle height which might not be 1 when called internally. Note that tests for negative count/width are left in place -- they are taken care of in the next patches. And document the hook. Signed-off-by: "Jiri Slaby (SUSE)" Cc: Helge Deller Cc: "James E.J. Bottomley" Cc: Daniel Vetter Cc: linux-fbdev@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linux-parisc@vger.kernel.org Tested-by: Helge Deller # parisc STI console Link: https://lore.kernel.org/r/20240122110401.7289-22-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 03bcbbb3995b ("dummycon: Trigger redraw when switching consoles with deferred takeover") Signed-off-by: Sasha Levin

tty: vt: make init parameter of consw::con_init() a bool

2025-07-06T08:57:59+00:00

[ Upstream commit dae3e6b6180f1a2394b984c596d39ed2c57d25fe ] The 'init' parameter of consw::con_init() is true for the first call of the hook on a particular console. So make the parameter a bool. And document the hook. Signed-off-by: "Jiri Slaby (SUSE)" Reviewed-by: Geert Uytterhoeven Cc: Helge Deller Cc: "James E.J. Bottomley" Cc: Daniel Vetter Cc: linux-fbdev@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Cc: linux-parisc@vger.kernel.org Tested-by: Helge Deller # parisc STI console Link: https://lore.kernel.org/r/20240122110401.7289-21-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman Stable-dep-of: 03bcbbb3995b ("dummycon: Trigger redraw when switching consoles with deferred takeover") Signed-off-by: Sasha Levin

vt: prevent kernel-infoleak in con_font_get()

2024-11-08T15:26:48+00:00

commit f956052e00de211b5c9ebaa1958366c23f82ee9e upstream. font.data may not initialize all memory spaces depending on the implementation of vc->vc_sw->con_font_get. This may cause info-leak, so to prevent this, it is safest to modify it to initialize the allocated memory space to 0, and it generally does not affect the overall performance of the system. Cc: stable@vger.kernel.org Reported-by: syzbot+955da2d57931604ee691@syzkaller.appspotmail.com Fixes: 05e2600cb0a4 ("VT: Bump font size limitation to 64x128 pixels") Signed-off-by: Jeongjun Park Link: https://lore.kernel.org/r/20241010174619.59662-1-aha310510@gmail.com Signed-off-by: Greg Kroah-Hartman

tty: add the option to have a tty reject a new ldisc

2024-06-27T11:46:17+00:00

[ Upstream commit 6bd23e0c2bb6c65d4f5754d1456bc9a4427fc59b ] ... and use it to limit the virtual terminals to just N_TTY. They are kind of special, and in particular, the "con_write()" routine violates the "writes cannot sleep" rule that some ldiscs rely on. This avoids the BUG: sleeping function called from invalid context at kernel/printk/printk.c:2659 when N_GSM has been attached to a virtual console, and gsmld_write() calls con_write() while holding a spinlock, and con_write() then tries to get the console lock. Tested-by: Tetsuo Handa Cc: Jiri Slaby Cc: Andrew Morton Cc: Daniel Starke Reported-by: syzbot Closes: https://syzkaller.appspot.com/bug?extid=dbac96d8e73b61aa559c Signed-off-by: Linus Torvalds Link: https://lore.kernel.org/r/20240423163339.59780-1-torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

vt: fix unicode buffer corruption when deleting characters

2024-04-03T13:19:42+00:00

commit 1581dafaf0d34bc9c428a794a22110d7046d186d upstream. This is the same issue that was fixed for the VGA text buffer in commit 39cdb68c64d8 ("vt: fix memory overlapping when deleting chars in the buffer"). The cure is also the same i.e. replace memcpy() with memmove() due to the overlaping buffers. Signed-off-by: Nicolas Pitre Fixes: 81732c3b2fed ("tty vt: Fix line garbage in virtual console on command line edition") Cc: stable Link: https://lore.kernel.org/r/sn184on2-3p0q-0qrq-0218-895349s4753o@syhkavp.arg Signed-off-by: Greg Kroah-Hartman

tty: vt: fix 20 vs 0x20 typo in EScsiignore

2024-03-26T22:20:57+00:00

[ Upstream commit 0e6a92f67c8a94707f7bb27ac29e2bdf3e7c167d ] The if (c >= 20 && c <= 0x3f) test added in commit 7a99565f8732 is wrong. 20 is DC4 in ascii and it makes no sense to consider that as the bottom limit. Instead, it should be 0x20 as in the other test in the commit above. This is supposed to NOT change anything as we handle interesting 20-0x20 asciis far before this if. So for sakeness, change to 0x20 (which is SPACE). Signed-off-by: "Jiri Slaby (SUSE)" Fixes: 7a99565f8732 ("vt: ignore csi sequences with intermediate characters.") Cc: Martin Hostettler Link: https://lore.kernel.org/all/ZaP45QY2WEsDqoxg@neutronstar.dyndns.org/ Tested-by: Helge Deller # parisc STI console Link: https://lore.kernel.org/r/20240122110401.7289-4-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

Merge 6.0-rc4 into tty-next

2022-09-05T05:59:28+00:00

We need the tty/serial fixes in here as well. Signed-off-by: Greg Kroah-Hartman

tty/vt: Add console_lock check to vt_console_print()

2022-09-01T14:58:08+00:00

I'm scratching my head why we have this printing_lock. Digging through historical git trees shows that: - Added in 1.1.73, and I found absolutely no reason why. - Converted to atomic bitops in 2.1.125pre2, I guess as part of SMP enabling/bugfixes. - Converted to a proper spinlock in b0940003f25d ("vt: bitlock fix") because the hand-rolled atomic version lacked necessary memory barriers. Digging around in lore for that time period did also not shed further light. The only reason I think this might still be relevant today is that (to my understanding at least, ymmv) during an oops we might be printing without console_lock held. See console_flush_on_panic() and the comments in there - we flush out the console buffers irrespective of whether we managed to acquire the right locks. The strange thing is that this reason is fairly recent, because the console flushing was historically done without oops_in_progress set. This only changed in c7c3f05e341a ("panic: avoid deadlocks in re-entrant console drivers"), which removed the call to bust_spinlocks(0) (which decrements oops_in_progress again) before flushing out the console (which back then was open coded as a console_trylock/unlock pair). Note that this entire mess should be properly fixed in the printk/console layer, and not inflicted on each implementation. For now just document what's going on and check that in all other cases callers obey the locking rules. v2: WARN_CONSOLE_UNLOCKED already checks for oops_in_progress (something else that should be fixed I guess), hence remove the open-coded check I've had. Signed-off-by: Daniel Vetter Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: "Ilpo Järvinen" Cc: Daniel Vetter Cc: Xuezhi Zhang Cc: Yangxi Xiang Cc: Tetsuo Handa Cc: nick black Cc: Petr Mladek Cc: Sergey Senozhatsky Cc: Steven Rostedt Cc: John Ogness Reviewed-by: Sam Ravnborg Link: https://lore.kernel.org/r/20220830144945.430528-1-daniel.vetter@ffwll.ch Signed-off-by: Greg Kroah-Hartman