kernel/linux.git/include/linux/leds.h, branch v5.10.257

leds: class: Protect brightness_show() with led_cdev->led_access mutex

2024-12-14T18:48:30+00:00

[ Upstream commit 4ca7cd938725a4050dcd62ae9472e931d603118d ] There is NULL pointer issue observed if from Process A where hid device being added which results in adding a led_cdev addition and later a another call to access of led_cdev attribute from Process B can result in NULL pointer issue. Use mutex led_cdev->led_access to protect access to led->cdev and its attribute inside brightness_show() and max_brightness_show() and also update the comment for mutex that it should be used to protect the led class device fields. Process A Process B kthread+0x114 worker_thread+0x244 process_scheduled_works+0x248 uhid_device_add_worker+0x24 hid_add_device+0x120 device_add+0x268 bus_probe_device+0x94 device_initial_probe+0x14 __device_attach+0xfc bus_for_each_drv+0x10c __device_attach_driver+0x14c driver_probe_device+0x3c __driver_probe_device+0xa0 really_probe+0x190 hid_device_probe+0x130 ps_probe+0x990 ps_led_register+0x94 devm_led_classdev_register_ext+0x58 led_classdev_register_ext+0x1f8 device_create_with_groups+0x48 device_create_groups_vargs+0xc8 device_add+0x244 kobject_uevent+0x14 kobject_uevent_env[jt]+0x224 mutex_unlock[jt]+0xc4 __mutex_unlock_slowpath+0xd4 wake_up_q+0x70 try_to_wake_up[jt]+0x48c preempt_schedule_common+0x28 __schedule+0x628 __switch_to+0x174 el0t_64_sync+0x1a8/0x1ac el0t_64_sync_handler+0x68/0xbc el0_svc+0x38/0x68 do_el0_svc+0x1c/0x28 el0_svc_common+0x80/0xe0 invoke_syscall+0x58/0x114 __arm64_sys_read+0x1c/0x2c ksys_read+0x78/0xe8 vfs_read+0x1e0/0x2c8 kernfs_fop_read_iter+0x68/0x1b4 seq_read_iter+0x158/0x4ec kernfs_seq_show+0x44/0x54 sysfs_kf_seq_show+0xb4/0x130 dev_attr_show+0x38/0x74 brightness_show+0x20/0x4c dualshock4_led_get_brightness+0xc/0x74 [ 3313.874295][ T4013] Unable to handle kernel NULL pointer dereference at virtual address 0000000000000060 [ 3313.874301][ T4013] Mem abort info: [ 3313.874303][ T4013] ESR = 0x0000000096000006 [ 3313.874305][ T4013] EC = 0x25: DABT (current EL), IL = 32 bits [ 3313.874307][ T4013] SET = 0, FnV = 0 [ 3313.874309][ T4013] EA = 0, S1PTW = 0 [ 3313.874311][ T4013] FSC = 0x06: level 2 translation fault [ 3313.874313][ T4013] Data abort info: [ 3313.874314][ T4013] ISV = 0, ISS = 0x00000006, ISS2 = 0x00000000 [ 3313.874316][ T4013] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 3313.874318][ T4013] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 3313.874320][ T4013] user pgtable: 4k pages, 39-bit VAs, pgdp=00000008f2b0a000 .. [ 3313.874332][ T4013] Dumping ftrace buffer: [ 3313.874334][ T4013] (ftrace buffer empty) .. .. [ dd3313.874639][ T4013] CPU: 6 PID: 4013 Comm: InputReader [ 3313.874648][ T4013] pc : dualshock4_led_get_brightness+0xc/0x74 [ 3313.874653][ T4013] lr : led_update_brightness+0x38/0x60 [ 3313.874656][ T4013] sp : ffffffc0b910bbd0 .. .. [ 3313.874685][ T4013] Call trace: [ 3313.874687][ T4013] dualshock4_led_get_brightness+0xc/0x74 [ 3313.874690][ T4013] brightness_show+0x20/0x4c [ 3313.874692][ T4013] dev_attr_show+0x38/0x74 [ 3313.874696][ T4013] sysfs_kf_seq_show+0xb4/0x130 [ 3313.874700][ T4013] kernfs_seq_show+0x44/0x54 [ 3313.874703][ T4013] seq_read_iter+0x158/0x4ec [ 3313.874705][ T4013] kernfs_fop_read_iter+0x68/0x1b4 [ 3313.874708][ T4013] vfs_read+0x1e0/0x2c8 [ 3313.874711][ T4013] ksys_read+0x78/0xe8 [ 3313.874714][ T4013] __arm64_sys_read+0x1c/0x2c [ 3313.874718][ T4013] invoke_syscall+0x58/0x114 [ 3313.874721][ T4013] el0_svc_common+0x80/0xe0 [ 3313.874724][ T4013] do_el0_svc+0x1c/0x28 [ 3313.874727][ T4013] el0_svc+0x38/0x68 [ 3313.874730][ T4013] el0t_64_sync_handler+0x68/0xbc [ 3313.874732][ T4013] el0t_64_sync+0x1a8/0x1ac Signed-off-by: Mukesh Ojha Reviewed-by: Anish Kumar Link: https://lore.kernel.org/r/20241103160527.82487-1-quic_mojha@quicinc.com Signed-off-by: Lee Jones Signed-off-by: Sasha Levin

leds: trigger: add support for LED-private device triggers

2020-07-22T12:42:07+00:00

Some LED controllers may come with an internal HW triggering mechanism for the LED and the ability to switch between SW control and the internal HW control. This includes most PHYs, various ethernet switches, the Turris Omnia LED controller or AXP20X PMIC. This adds support for registering such triggers. This code is based on work by Pavel Machek and Ondřej Jirman . Signed-off-by: Marek Behún Acked-by: Jacek Anaszewski Signed-off-by: Pavel Machek

leds: old enums are not really applicable to new code

2020-04-06T20:55:27+00:00

Warn about old defines that probably should not be used. Signed-off-by: Pavel Machek

leds: Add managed API to get a LED from a device driver

2020-01-05T23:20:18+00:00

If the LED is acquired by a consumer device with devm_led_get(), it is automatically released when the device is detached. Signed-off-by: Jean-Jacques Hiblot Acked-by: Pavel Machek Signed-off-by: Pavel Machek

leds: Add of_led_get() and led_put()

2020-01-05T23:20:06+00:00

This patch adds basic support for a kernel driver to get a LED device. This will be used by the led-backlight driver. Only OF version is implemented for now, and the behavior is similar to PWM's of_pwm_get() and pwm_put(). Signed-off-by: Tomi Valkeinen Signed-off-by: Jean-Jacques Hiblot Acked-by: Pavel Machek Signed-off-by: Pavel Machek

leds: core: Fix leds.h structure documentation

2019-11-03T16:38:55+00:00

Update the leds.h structure documentation to define the correct arguments. Signed-off-by: Dan Murphy Signed-off-by: Pavel Machek

leds: core: Remove extern from header

2019-11-03T16:38:46+00:00

extern is implied and is not needed in the header file. Remove the extern keyword and re-align the code. Signed-off-by: Dan Murphy Signed-off-by: Pavel Machek

leds: remove PAGE_SIZE limit of /sys/class/leds//trigger

2019-11-03T16:38:14+00:00

Reading /sys/class/leds//trigger returns all available LED triggers. However, the size of this file is limited to PAGE_SIZE because of the limitation for sysfs attribute. Enabling LED CPU trigger on systems with thousands of CPUs easily hits PAGE_SIZE limit, and makes it impossible to see all available LED triggers and which trigger is currently activated. We work around it here by converting /sys/class/leds//trigger to binary attribute, which is not limited by length. This is _not_ good design, do not copy it. Signed-off-by: Akinobu Mita Cc: "Rafael J. Wysocki" Cc: Pavel Machek Cc: Dan Murphy A Reviewed-by: Greg Kroah-Hartman Signed-off-by: Pavel Machek

leds: Replace {devm_}led_classdev_register() macros with inlines

2019-09-01T11:33:16+00:00

Replace preprocessor macro aliases for legacy LED registration helpers with inline functions. It will allow to avoid misleading compiler error messages about missing symbol that actually wasn't explicitly used in the code. It used to occur when CONFIG_LEDS_CLASS was undefined and legacy (non-ext) function had been used in the code. Signed-off-by: Jacek Anaszewski Acked-by: Pavel Machek

leds: core: Add support for composing LED class device names

2019-07-25T18:07:52+00:00

Add generic support for composing LED class device name. The newly introduced led_compose_name() function composes device name according to either or pattern, depending on the configuration of initialization data. Backward compatibility with in-driver hard-coded LED class device names is assured thanks to the default_label and devicename properties of newly introduced struct led_init_data. In case none of the aforementioned properties was found, then, for OF nodes, the node name is adopted for LED class device name. At the occassion of amending the Documentation/leds/leds-class.txt unify spelling: colour -> color. Alongside these changes added is a new tool - tools/leds/get_led_device_info.sh. The tool allows retrieving details of a LED class device's parent device, which proves that using vendor or product name for devicename part of LED name doesn't convey any added value since that information had been already available in sysfs. The script performs also basic validation of a LED class device name. Signed-off-by: Jacek Anaszewski Cc: Baolin Wang Cc: Dan Murphy Cc: Daniel Mack Cc: Linus Walleij Cc: Oleh Kravchenko Cc: Sakari Ailus Cc: Simon Shields Reviewed-by: Linus Walleij Acked-by: Pavel Machek