kernel/linux.git/drivers/tty/sysrq.c, branch v6.12.80

Merge tag 'v6.11-rc1' into for-6.12

2024-07-30T19:30:11+00:00

Linux 6.11-rc1

Merge tag 'devicetree-fixes-for-6.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux

2024-07-27T19:46:16+00:00

Pull more devicetree updates from Rob Herring: "Most of this is a treewide change to of_property_for_each_u32() which was small enough to do in one go before rc1 and avoids the need to create of_property_for_each_u32_some_new_name(). - Treewide conversion of of_property_for_each_u32() to drop internal arguments making struct property opaque - Add binding for Amlogic A4 SoC watchdog - Fix constraints for AD7192 'single-channel' property" * tag 'devicetree-fixes-for-6.11-1' of git://git.kernel.org/pub/scm/linux/kernel/git/robh/linux: dt-bindings: iio: adc: ad7192: Fix 'single-channel' constraints of: remove internal arguments from of_property_for_each_u32() dt-bindings: watchdog: add support for Amlogic A4 SoCs

of: remove internal arguments from of_property_for_each_u32()

2024-07-25T11:53:47+00:00

The of_property_for_each_u32() macro needs five parameters, two of which are primarily meant as internal variables for the macro itself (in the for() clause). Yet these two parameters are used by a few drivers, and this can be considered misuse or at least bad practice. Now that the kernel uses C11 to build, these two parameters can be avoided by declaring them internally, thus changing this pattern: struct property *prop; const __be32 *p; u32 val; of_property_for_each_u32(np, "xyz", prop, p, val) { ... } to this: u32 val; of_property_for_each_u32(np, "xyz", val) { ... } However two variables cannot be declared in the for clause even with C11, so declare one struct that contain the two variables we actually need. As the variables inside this struct are not meant to be used by users of this macro, give the struct instance the noticeable name "_it" so it is visible during code reviews, helping to avoid new code to use it directly. Most usages are trivially converted as they do not use those two parameters, as expected. The non-trivial cases are: - drivers/clk/clk.c, of_clk_get_parent_name(): easily doable anyway - drivers/clk/clk-si5351.c, si5351_dt_parse(): this is more complex as the checks had to be replicated in a different way, making code more verbose and somewhat uglier, but I refrained from a full rework to keep as much of the original code untouched having no hardware to test my changes All the changes have been build tested. The few for which I have the hardware have been runtime-tested too. Reviewed-by: Andre Przywara # drivers/clk/sunxi/clk-simple-gates.c, drivers/clk/sunxi/clk-sun8i-bus-gates.c Acked-by: Bartosz Golaszewski # drivers/gpio/gpio-brcmstb.c Acked-by: Nicolas Ferre # drivers/irqchip/irq-atmel-aic-common.c Acked-by: Jonathan Cameron # drivers/iio/adc/ti_am335x_adc.c Acked-by: Uwe Kleine-König # drivers/pwm/pwm-samsung.c Acked-by: Richard Leitner # drivers/usb/misc/usb251xb.c Acked-by: Mark Brown # sound/soc/codecs/arizona.c Reviewed-by: Richard Fitzgerald # sound/soc/codecs/arizona.c Acked-by: Michael Ellerman # arch/powerpc/sysdev/xive/spapr.c Acked-by: Stephen Boyd # clk Signed-off-by: Luca Ceresoli Acked-by: Lee Jones Link: https://lore.kernel.org/r/20240724-of_property_for_each_u32-v3-1-bea82ce429e2@bootlin.com Signed-off-by: Rob Herring (Arm)

sched_ext: Add sysrq-S which disables the BPF scheduler

2024-06-18T20:09:18+00:00

This enables the admin to abort the BPF scheduler and revert to CFS anytime. Signed-off-by: Tejun Heo Reviewed-by: David Vernet Acked-by: Josh Don Acked-by: Hao Luo Acked-by: Barret Rhoden

printk: Rename console_replay_all() and update context

2024-06-03T15:17:29+00:00

Rename console_replay_all() to console_try_replay_all() to make clear that the implementation is best effort. Also, the function should not be called in NMI context as it takes locks, so update the comment in code. Fixes: 693f75b91a91 ("printk: Add function to replay kernel log on consoles") Fixes: 1b743485e27f ("tty/sysrq: Replay kernel log messages on consoles via sysrq") Suggested-by: Petr Mladek Signed-off-by: Shimoyashiki Taichi Signed-off-by: Sreenath Vijayan Link: https://lore.kernel.org/r/Zlguq/wU21Z8MqI4@sreenath.vijayan@sony.com Reviewed-by: Petr Mladek Signed-off-by: Petr Mladek

tty/sysrq: Replay kernel log messages on consoles via sysrq

2024-04-11T12:22:52+00:00

When terminal is unresponsive, one cannot use dmesg to view the printk ring buffer messages. Also, syslog services may be disabled, especially on embedded systems, to check the messages after a reboot. In this scenario, replay the messages in printk ring buffer on consoles via sysrq by pressing sysrq+R. The console loglevel will determine which all kernel log messages are displayed. The messages will be displayed only when console_trylock() succeeds. Users could repeat the sysrq key when it fails. If the owner of console subsystem lock is stuck, repeating the key won't work. Suggested-by: Petr Mladek Signed-off-by: Shimoyashiki Taichi Reviewed-by: John Ogness Signed-off-by: Sreenath Vijayan Link: https://lore.kernel.org/r/cc3b9b1aae60a236c6aed1dc7b0ffa2c7cd1f183.1710220326.git.sreenath.vijayan@sony.com Signed-off-by: Greg Kroah-Hartman

/proc/sysrq-trigger: accept multiple keys at once

2023-11-25T07:23:16+00:00

This way we can do: `echo _reisub > /proc/sysrq-trigger` Instead of: `for i in r e i s u b; do echo "$i" > /proc/sysrq-trigger; done;` This can be very useful when trying to execute sysrq combo remotely or from userspace. When sending keys in multiple separate writes, userspace (eg. bash or ssh) can be killed before whole combo is completed. Therefore putting all keys in single write is more robust approach. Signed-off-by: Tomas Mudrunka Reviewed-by: Jiri Slaby Link: https://lore.kernel.org/r/20231120111451.527952-1-tomas.mudrunka@gmail.com Signed-off-by: Greg Kroah-Hartman

tty/sysrq: replace smp_processor_id() with get_cpu()

2023-10-10T06:52:24+00:00

The smp_processor_id() shouldn't be called from preemptible code. Instead use get_cpu() and put_cpu() which disables preemption in addition to getting the processor id. Enable preemption back after calling schedule_work() to make sure that the work gets scheduled on all cores other than the current core. We want to avoid a scenario where current core's stack trace is printed multiple times and one core's stack trace isn't printed because of scheduling of current task. This fixes the following bug: [ 119.143590] sysrq: Show backtrace of all active CPUs [ 119.143902] BUG: using smp_processor_id() in preemptible [00000000] code: bash/873 [ 119.144586] caller is debug_smp_processor_id+0x20/0x30 [ 119.144827] CPU: 6 PID: 873 Comm: bash Not tainted 5.10.124-dirty #3 [ 119.144861] Hardware name: QEMU QEMU Virtual Machine, BIOS 2023.05-1 07/22/2023 [ 119.145053] Call trace: [ 119.145093] dump_backtrace+0x0/0x1a0 [ 119.145122] show_stack+0x18/0x70 [ 119.145141] dump_stack+0xc4/0x11c [ 119.145159] check_preemption_disabled+0x100/0x110 [ 119.145175] debug_smp_processor_id+0x20/0x30 [ 119.145195] sysrq_handle_showallcpus+0x20/0xc0 [ 119.145211] __handle_sysrq+0x8c/0x1a0 [ 119.145227] write_sysrq_trigger+0x94/0x12c [ 119.145247] proc_reg_write+0xa8/0xe4 [ 119.145266] vfs_write+0xec/0x280 [ 119.145282] ksys_write+0x6c/0x100 [ 119.145298] __arm64_sys_write+0x20/0x30 [ 119.145315] el0_svc_common.constprop.0+0x78/0x1e4 [ 119.145332] do_el0_svc+0x24/0x8c [ 119.145348] el0_svc+0x10/0x20 [ 119.145364] el0_sync_handler+0x134/0x140 [ 119.145381] el0_sync+0x180/0x1c0 Cc: jirislaby@kernel.org Cc: stable@vger.kernel.org Fixes: 47cab6a722d4 ("debug lockups: Improve lockup detection, fix generic arch fallback") Signed-off-by: Muhammad Usama Anjum Link: https://lore.kernel.org/r/20231009162021.3607632-1-usama.anjum@collabora.com Signed-off-by: Greg Kroah-Hartman

Merge tag 'tty-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

2023-09-01T16:38:00+00:00

Pull tty/serial driver updates from Greg KH: "Here is the big set of tty and serial driver changes for 6.6-rc1. Lots of cleanups in here this cycle, and some driver updates. Short summary is: - Jiri's continued work to make the tty code and apis be a bit more sane with regards to modern kernel coding style and types - cpm_uart driver updates - n_gsm updates and fixes - meson driver updates - sc16is7xx driver updates - 8250 driver updates for different hardware types - qcom-geni driver fixes - tegra serial driver change - stm32 driver updates - synclink_gt driver cleanups - tty structure size reduction All of these have been in linux-next this week with no reported issues. The last bit of cleanups from Jiri and the tty structure size reduction came in last week, a bit late but as they were just style changes and size reductions, I figured they should get into this merge cycle so that others can work on top of them with no merge conflicts" * tag 'tty-6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (199 commits) tty: shrink the size of struct tty_struct by 40 bytes tty: n_tty: deduplicate copy code in n_tty_receive_buf_real_raw() tty: n_tty: extract ECHO_OP processing to a separate function tty: n_tty: unify counts to size_t tty: n_tty: use u8 for chars and flags tty: n_tty: simplify chars_in_buffer() tty: n_tty: remove unsigned char casts from character constants tty: n_tty: move newline handling to a separate function tty: n_tty: move canon handling to a separate function tty: n_tty: use MASK() for masking out size bits tty: n_tty: make n_tty_data::num_overrun unsigned tty: n_tty: use time_is_before_jiffies() in n_tty_receive_overrun() tty: n_tty: use 'num' for writes' counts tty: n_tty: use output character directly tty: n_tty: make flow of n_tty_receive_buf_common() a bool Revert "tty: serial: meson: Add a earlycon for the T7 SoC" Documentation: devices.txt: Fix minors for ttyCPM* Documentation: devices.txt: Remove ttySIOC* Documentation: devices.txt: Remove ttyIOC* serial: 8250_bcm7271: improve bcm7271 8250 port ...

mm: remove arguments of show_mem()

2023-08-18T17:12:02+00:00

All callers of show_mem() pass 0 and NULL, so we can remove the two arguments by directly calling __show_mem(0, NULL, MAX_NR_ZONES - 1) in show_mem(). Link: https://lkml.kernel.org/r/20230630062253.189440-1-wangkefeng.wang@huawei.com Signed-off-by: Kefeng Wang Cc: Christophe Leroy Cc: Greg Kroah-Hartman Cc: Matthew Wilcox Cc: Michael Ellerman Cc: Nicholas Piggin Signed-off-by: Andrew Morton