user/sven/linux.git/include/linux/leds.h, branch v6.1.162

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

2024-12-14T18:54:46Z

[ 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: Store brightness set by led_trigger_event()

2024-08-11T10:35:53Z

[ Upstream commit 822c91e72eac568ed8d83765634f00decb45666c ] If a simple trigger is assigned to a LED, then the LED may be off until the next led_trigger_event() call. This may be an issue for simple triggers with rare led_trigger_event() calls, e.g. power supply charging indicators (drivers/power/supply/power_supply_leds.c). Therefore persist the brightness value of the last led_trigger_event() call and use this value if the trigger is assigned to a LED. In addition add a getter for the trigger brightness value. Signed-off-by: Heiner Kallweit Reviewed-by: Takashi Iwai Link: https://lore.kernel.org/r/b1358b25-3f30-458d-8240-5705ae007a8a@gmail.com Signed-off-by: Lee Jones Stable-dep-of: ab477b766edd ("leds: triggers: Flush pending brightness before activating trigger") Signed-off-by: Sasha Levin

leds: trigger: Remove unused function led_trigger_rename_static()

2024-08-11T10:35:53Z

[ Upstream commit c82a1662d4548c454de5343b88f69b9fc82266b3 ] This function was added with a8df7b1ab70b ("leds: add led_trigger_rename function") 11 yrs ago, but it has no users. So remove it. Signed-off-by: Heiner Kallweit Link: https://lore.kernel.org/r/d90f30be-f661-4db7-b0b5-d09d07a78a68@gmail.com Signed-off-by: Lee Jones Stable-dep-of: ab477b766edd ("leds: triggers: Flush pending brightness before activating trigger") Signed-off-by: Sasha Levin

leds: trigger: use RCU to protect the led_cdevs list

2021-09-27T14:16:42Z

Even with the previous commit 27af8e2c90fb ("leds: trigger: fix potential deadlock with libata") to this file, we still get lockdep unhappy, and Boqun explained the report here: https://lore.kernel.org/r/YNA+d1X4UkoQ7g8a@boqun-archlinux Effectively, this means that the read_lock_irqsave() isn't enough here because another CPU might be trying to do a write lock, and thus block the readers. This is all pretty messy, but it doesn't seem right that the LEDs framework imposes some locking requirements on users, in particular we'd have to make the spinlock in the iwlwifi driver always disable IRQs, even if we don't need that for any other reason, just to avoid this deadlock. Since writes to the led_cdevs list are rare (and are done by userspace), just switch the list to RCU. This costs a synchronize_rcu() at removal time so we can ensure things are correct, but that seems like a small price to pay for getting lock-free iterations and no deadlocks (nor any locking requirements imposed on users.) Signed-off-by: Johannes Berg Signed-off-by: Pavel Machek

leds: move default_state read from fwnode to core

2021-08-18T06:27:30Z

This patch introduces a new function to read initial default_state from fwnode. Suggested-by: Pavel Machek Signed-off-by: Denis Osterland-Heim Signed-off-by: Pavel Machek

leds: led-core: Get rid of enum led_brightness

2021-02-19T10:35:28Z

This gets rid of enum led_brightness in the main led files, because it is deprecated, and an unsigned int can be used instead. We can get rid of led_brightness completely and patches can also be supplied for the other drivers' files. Signed-off-by: Abanoub Sameh Signed-off-by: Pavel Machek

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

2020-07-22T12:42:07Z

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

2020-04-06T20:55:27Z

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

2020-01-05T23:20:18Z

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()

2020-01-05T23:20:06Z

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