user/sven/linux.git/drivers/tty/tty_buffer.c, branch v5.15.27

tty: tty_buffer: Fix the softlockup issue in flush_to_ldisc

2021-11-25T08:48:28Z

[ Upstream commit 3968ddcf05fb4b9409cd1859feb06a5b0550a1c1 ] When running ltp testcase(ltp/testcases/kernel/pty/pty04.c) with arm64, there is a soft lockup, which look like this one: Workqueue: events_unbound flush_to_ldisc Call trace: dump_backtrace+0x0/0x1ec show_stack+0x24/0x30 dump_stack+0xd0/0x128 panic+0x15c/0x374 watchdog_timer_fn+0x2b8/0x304 __run_hrtimer+0x88/0x2c0 __hrtimer_run_queues+0xa4/0x120 hrtimer_interrupt+0xfc/0x270 arch_timer_handler_phys+0x40/0x50 handle_percpu_devid_irq+0x94/0x220 __handle_domain_irq+0x88/0xf0 gic_handle_irq+0x84/0xfc el1_irq+0xc8/0x180 slip_unesc+0x80/0x214 [slip] tty_ldisc_receive_buf+0x64/0x80 tty_port_default_receive_buf+0x50/0x90 flush_to_ldisc+0xbc/0x110 process_one_work+0x1d4/0x4b0 worker_thread+0x180/0x430 kthread+0x11c/0x120 In the testcase pty04, The first process call the write syscall to send data to the pty master. At the same time, the workqueue will do the flush_to_ldisc to pop data in a loop until there is no more data left. When the sender and workqueue running in different core, the sender sends data fastly in full time which will result in workqueue doing work in loop for a long time and occuring softlockup in flush_to_ldisc with kernel configured without preempt. So I add need_resched check and cond_resched in the flush_to_ldisc loop to avoid it. Signed-off-by: Guanghui Feng Link: https://lore.kernel.org/r/1633961304-24759-1-git-send-email-guanghuifeng@linux.alibaba.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

tty: tty_buffer: Fix incorrectly documented function __tty_buffer_request_room()

2021-05-20T15:06:15Z

Fixes the following W=1 kernel build warning(s): drivers/tty/tty_buffer.c:259: warning: expecting prototype for tty_buffer_request_room(). Prototype was for __tty_buffer_request_room() instead Cc: Greg Kroah-Hartman Cc: Jiri Slaby Signed-off-by: Lee Jones Link: https://lore.kernel.org/r/20210520121906.3468725-6-lee.jones@linaro.org Signed-off-by: Greg Kroah-Hartman

tty: tty_buffer: Fix coding style issues of block comments

2021-05-13T16:29:12Z

Fix coding style issues of block comments, reported by checkpatch.pl. Besides, add a period at the end of the sentenses. Signed-off-by: Xiaofei Tan Link: https://lore.kernel.org/r/1620811585-18582-6-git-send-email-tanxiaofei@huawei.com Signed-off-by: Greg Kroah-Hartman

tty: tty_buffer: Remove the repeated word 'the'

2021-05-13T16:29:12Z

Remove the repeated word 'the' following advice of checkpatch.pl Besides, add a period at the end of comment sentence. Signed-off-by: Xiaofei Tan Link: https://lore.kernel.org/r/1620811585-18582-5-git-send-email-tanxiaofei@huawei.com Signed-off-by: Greg Kroah-Hartman

tty: tty_buffer: Add a blank line after declarations

2021-05-13T16:29:12Z

Add a blank line after declarations, reported by checkpatch.pl. Signed-off-by: Xiaofei Tan Link: https://lore.kernel.org/r/1620811585-18582-4-git-send-email-tanxiaofei@huawei.com Signed-off-by: Greg Kroah-Hartman

tty: make tty_buffer_space_avail return uint

2021-05-13T16:29:11Z

tty_buffer_space_avail returns values >= 0, so make it clear by the return type. Signed-off-by: Jiri Slaby Cc: Joel Stanley Link: https://lore.kernel.org/r/20210505091928.22010-25-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: make fp of tty_ldisc_ops::receive_buf{,2} const

2021-05-13T14:57:16Z

Char pointer (cp) passed to tty_ldisc_ops::receive_buf{,2} is const. There is no reason for flag pointer (fp) not to be too. So switch it in the definition and all uses. 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: Liam Girdwood Cc: Mark Brown Cc: Jaroslav Kysela Cc: Takashi Iwai Cc: Peter Ujfalusi Link: https://lore.kernel.org/r/20210505091928.22010-12-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman

tty: move some internal tty lock enums and functions out of tty.h

2021-04-15T08:26:58Z

Move the TTY_LOCK_* enums and tty_ldisc lock functions out of the global tty.h into the local header file to clean things up. Cc: Jiri Slaby Link: https://lore.kernel.org/r/20210408125134.3016837-10-gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman

tty: tty_buffer: Add missing description for 'limit'

2020-11-06T09:49:27Z

Fixes the following W=1 kernel build warning(s): drivers/tty/tty_buffer.c:592: warning: Function parameter or member 'limit' not described in 'tty_buffer_set_limit' Cc: Greg Kroah-Hartman Cc: Jiri Slaby Signed-off-by: Lee Jones Link: https://lore.kernel.org/r/20201104193549.4026187-6-lee.jones@linaro.org Signed-off-by: Greg Kroah-Hartman

tty: fix kernel-doc

2020-08-18T11:51:18Z

With W=1, the kernel-doc checker complains quite a lot in the tty layer. Over the time, many documented parameters were renamed, removed or switched from tty to tty_port and similar. Some were mistyped in the doc too. So fix all these in the tty core. (But do not add the missing ones which the checker complains about too. Not now.) The rest in the tty layer will follow in the next patches. Signed-off-by: Jiri Slaby Link: https://lore.kernel.org/r/20200818085655.12071-4-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman