kernel/linux.git/drivers/tty/tty_ldisc.c, branch v6.6.132

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

2024-06-27T11:49:05+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

tty: tty_ldisc: Remove the ret variable

2023-03-09T16:11:18+00:00

The int variable ret does not receive the return value in this function. It should be removed and returned 0 directly. Signed-off-by: Li zeming Reviewed-by: Jiri Slaby Link: https://lore.kernel.org/r/20230222202303.3195-1-zeming@nfschina.com Signed-off-by: Greg Kroah-Hartman

tty: Move sysctl setup into "core" tty logic

2022-11-03T00:58:03+00:00

In preparation for adding another sysctl to the tty subsystem, move the tty setup code into the "core" tty code, which contains tty_init() itself. Cc: Greg Kroah-Hartman Cc: Jiri Slaby Signed-off-by: Kees Cook Link: https://lore.kernel.org/r/20221022182949.2684794-1-keescook@chromium.org Signed-off-by: Greg Kroah-Hartman

tty: reformat kernel-doc in tty_ldisc.c

2021-11-26T15:27:43+00:00

Kernel-doc is a bit strict about some formatting. So fix these: 1) When there is a tab in comments, it thinks the line is a continuation one. So the description of the functions end up as descriptions of the last parameter described. Remove the tabs. 2) Remove newlines before parameters description and after the comments. This was not wrong per se, only inconsistent with the rest of the file. 3) Add periods to the end of sentences where appropriate. 4) Add "()" to function names and "%" to constants, so that they are properly highlighted. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20211126081611.11001-14-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: unexport tty_ldisc_release

2021-09-14T09:18:47+00:00

Initially, tty_ldisc_release() was exported for speakup (spk_tty) while in staging. Later, the call to this function was removed as it was bogus anyway. Remove the export now. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210914091134.17426-1-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: tty_ldisc: fix doc warnings in tty_ldisc.c

2021-06-09T12:43:23+00:00

Fixes the following W=1 kernel build warning(s): drivers/tty/tty_ldisc.c:63: warning: Excess function parameter 'disc' description in 'tty_register_ldisc' drivers/tty/tty_ldisc.c:90: warning: Function parameter or member 'ldisc' not described in 'tty_unregister_ldisc' drivers/tty/tty_ldisc.c:90: warning: Excess function parameter 'disc' description in 'tty_unregister_ldisc' Signed-off-by: Baokun Li Link: https://lore.kernel.org/r/20210608024843.2756746-1-libaokun1@huawei.com Signed-off-by: Greg Kroah-Hartman

tty: return void from tty_unregister_ldisc

2021-05-13T14:57:17+00:00

Now that noone checks the return value of tty_unregister_ldisc, make the function return 'void'. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210505091928.22010-20-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: drop tty_ldisc_ops::refcount

2021-05-13T14:57:17+00:00

The refcount is checked only in tty_unregister_ldisc and EBUSY returned if it is nonzero. But none of the tty_unregister_ldisc callers act anyhow if this (or any other) error is returned. So remove tty_ldisc_ops::refcount completely and make tty_unregister_ldisc return 'void' in the next patches. That means we assume tty_unregister_ldisc is not called while the ldisc might be in use. That relies on try_module_get in get_ldops and module_put in put_ldops. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20210505091928.22010-18-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: make tty_ldisc_ops a param in tty_unregister_ldisc

2021-05-13T14:57:16+00:00

Make tty_unregister_ldisc symmetric to tty_register_ldisc by accepting struct tty_ldisc_ops as a parameter instead of ldisc number. This avoids checking of the ldisc number bounds in tty_unregister_ldisc. Signed-off-by: Jiri Slaby Cc: William Hubbs Cc: Chris Brannon Cc: Kirk Reiser Cc: Samuel Thibault Cc: Marcel Holtmann Cc: Johan Hedberg Cc: Luiz Augusto von Dentz Cc: Dmitry Torokhov Cc: Arnd Bergmann Cc: "David S. Miller" Cc: Jakub Kicinski Cc: Wolfgang Grandegger Cc: Marc Kleine-Budde Cc: Andreas Koensgen Cc: Paul Mackerras Cc: Rodolfo Giometti Cc: Peter Ujfalusi Cc: Liam Girdwood Cc: Mark Brown Cc: Jaroslav Kysela Cc: Takashi Iwai Link: https://lore.kernel.org/r/20210505091928.22010-17-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: set tty_ldisc_ops::num statically

2021-05-13T14:57:16+00:00

There is no reason to pass the ldisc number to tty_register_ldisc separately. Just set it in the already defined tty_ldisc_ops in all the ldiscs. This simplifies tty_register_ldisc a bit too (no need to set the num member there). Signed-off-by: Jiri Slaby Cc: William Hubbs Cc: Chris Brannon Cc: Kirk Reiser Cc: Samuel Thibault Cc: Marcel Holtmann Cc: Johan Hedberg Cc: Luiz Augusto von Dentz Cc: Dmitry Torokhov Cc: Arnd Bergmann Cc: "David S. Miller" Cc: Jakub Kicinski Cc: Wolfgang Grandegger Cc: Marc Kleine-Budde Cc: Andreas Koensgen Cc: Paul Mackerras Cc: Rodolfo Giometti Cc: Peter Ujfalusi Cc: Liam Girdwood Cc: Mark Brown Cc: Jaroslav Kysela Cc: Takashi Iwai Link: https://lore.kernel.org/r/20210505091928.22010-15-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman