From 506ada89629ec7059b96ecfb0dc7d33ece0103ca Mon Sep 17 00:00:00 2001 From: Eduard Zingerman Date: Fri, 4 Sep 2026 17:05:56 -0700 Subject: bpf: mark a NULL kfunc argument precise check_kfunc_arg() allows bpf_register_is_null() for nullable arguments w/o marking the underlying scalar register precise. Hence a checkpoint created on such a path would prune against arbitrary scalar value. Fixes: 3bda08b63670 ("bpf: Allow NULL buffers in bpf_dynptr_slice(_rw)") Signed-off-by: Eduard Zingerman Link: https://lore.kernel.org/r/20260904-register-is-null-precise-fixes-v1-5-0f5a360ff15d@gmail.com Signed-off-by: Alexei Starovoitov --- drivers/leds/trigger/ledtrig-backlight.c | 140 +++++++++++++++++++++++++++++++ 1 file changed, 140 insertions(+) create mode 100644 drivers/leds/trigger/ledtrig-backlight.c (limited to 'drivers/leds/trigger/ledtrig-backlight.c') diff --git a/drivers/leds/trigger/ledtrig-backlight.c b/drivers/leds/trigger/ledtrig-backlight.c new file mode 100644 index 000000000..e67bc7c2a --- /dev/null +++ b/drivers/leds/trigger/ledtrig-backlight.c @@ -0,0 +1,140 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Backlight emulation LED trigger + * + * Copyright 2008 (C) Rodolfo Giometti + * Copyright 2008 (C) Eurotech S.p.A. + */ + +#include +#include +#include +#include +#include +#include "../leds.h" + +#define BLANK 1 +#define UNBLANK 0 + +struct bl_trig_notifier { + struct led_classdev *led; + int brightness; + int old_status; + unsigned invert; + + struct list_head entry; +}; + +static DEFINE_MUTEX(ledtrig_backlight_list_mutex); +static LIST_HEAD(ledtrig_backlight_list); + +static void ledtrig_backlight_notify_blank(struct bl_trig_notifier *n, int new_status) +{ + struct led_classdev *led = n->led; + + if (new_status == n->old_status) + return; + + if ((n->old_status == UNBLANK) ^ n->invert) { + n->brightness = led->brightness; + led_set_brightness_nosleep(led, LED_OFF); + } else { + led_set_brightness_nosleep(led, n->brightness); + } + + n->old_status = new_status; +} + +void ledtrig_backlight_blank(bool blank) +{ + struct bl_trig_notifier *n; + int new_status = blank ? BLANK : UNBLANK; + + guard(mutex)(&ledtrig_backlight_list_mutex); + + list_for_each_entry(n, &ledtrig_backlight_list, entry) + ledtrig_backlight_notify_blank(n, new_status); +} +EXPORT_SYMBOL(ledtrig_backlight_blank); + +static ssize_t bl_trig_invert_show(struct device *dev, + struct device_attribute *attr, char *buf) +{ + struct bl_trig_notifier *n = led_trigger_get_drvdata(dev); + + return sprintf(buf, "%u\n", n->invert); +} + +static ssize_t bl_trig_invert_store(struct device *dev, + struct device_attribute *attr, const char *buf, size_t num) +{ + struct led_classdev *led = led_trigger_get_led(dev); + struct bl_trig_notifier *n = led_trigger_get_drvdata(dev); + unsigned long invert; + int ret; + + ret = kstrtoul(buf, 10, &invert); + if (ret < 0) + return ret; + + if (invert > 1) + return -EINVAL; + + n->invert = invert; + + /* After inverting, we need to update the LED. */ + if ((n->old_status == BLANK) ^ n->invert) + led_set_brightness_nosleep(led, LED_OFF); + else + led_set_brightness_nosleep(led, n->brightness); + + return num; +} +static DEVICE_ATTR(inverted, 0644, bl_trig_invert_show, bl_trig_invert_store); + +static struct attribute *bl_trig_attrs[] = { + &dev_attr_inverted.attr, + NULL, +}; +ATTRIBUTE_GROUPS(bl_trig); + +static int bl_trig_activate(struct led_classdev *led) +{ + struct bl_trig_notifier *n; + + n = kzalloc_obj(struct bl_trig_notifier); + if (!n) + return -ENOMEM; + led_set_trigger_data(led, n); + + n->led = led; + n->brightness = led->brightness; + n->old_status = UNBLANK; + + guard(mutex)(&ledtrig_backlight_list_mutex); + list_add(&n->entry, &ledtrig_backlight_list); + + return 0; +} + +static void bl_trig_deactivate(struct led_classdev *led) +{ + struct bl_trig_notifier *n = led_get_trigger_data(led); + + guard(mutex)(&ledtrig_backlight_list_mutex); + list_del(&n->entry); + + kfree(n); +} + +static struct led_trigger bl_led_trigger = { + .name = "backlight", + .activate = bl_trig_activate, + .deactivate = bl_trig_deactivate, + .groups = bl_trig_groups, +}; +module_led_trigger(bl_led_trigger); + +MODULE_AUTHOR("Rodolfo Giometti "); +MODULE_DESCRIPTION("Backlight emulation LED trigger"); +MODULE_LICENSE("GPL v2"); -- cgit v1.3.1