![Rafał Miłecki](/assets/img/avatar_default.png)
Calling brightness_set manually isn't safe as some LED drivers don't
implement this callback. The best idea is to just use a proper helper
which will fallback to the brightness_set_blocking callback if needed.
This fixes:
[ 1461.761528] Unable to handle kernel NULL pointer dereference at virtual address 00000000
(...)
[ 1462.117049] Backtrace:
[ 1462.119521] [<bf228164>] (usbport_trig_port_store [ledtrig_usbport]) from [<c023f758>] (dev_attr_store+0x20/0x2c)
[ 1462.129826] r7:dcabc7c0 r6:dee0ff80 r5:00000002 r4:bf228164
[ 1462.135511] [<c023f738>] (dev_attr_store) from [<c0169310>] (sysfs_kf_write+0x48/0x4c)
[ 1462.143459] r5:00000002 r4:c023f738
[ 1462.147049] [<c01692c8>] (sysfs_kf_write) from [<c0168ab8>] (kernfs_fop_write+0xf8/0x1f8)
[ 1462.155258] r5:00000002 r4:df4a1000
[ 1462.158850] [<c01689c0>] (kernfs_fop_write) from [<c0100c78>] (__vfs_write+0x34/0x120)
[ 1462.166800] r10:00000000 r9:dee0e000 r8:c000fc24 r7:00000002 r6:dee0ff80 r5:c01689c0
[ 1462.174660] r4:df727a80
[ 1462.177204] [<c0100c44>] (__vfs_write) from [<c0101ae4>] (vfs_write+0xac/0x170)
[ 1462.184543] r9:dee0e000 r8:c000fc24 r7:dee0ff80 r6:b6f092d0 r5:df727a80 r4:00000002
[ 1462.192319] [<c0101a38>] (vfs_write) from [<c01028dc>] (SyS_write+0x4c/0xa8)
[ 1462.199396] r9:dee0e000 r8:c000fc24 r7:00000002 r6:b6f092d0 r5:df727a80 r4:df727a80
[ 1462.207174] [<c0102890>] (SyS_write) from [<c000fa60>] (ret_fast_syscall+0x0/0x3c)
[ 1462.214774] r7:00000004 r6:ffffffff r5:00000000 r4:00000000
[ 1462.220456] Code: bad PC value
[ 1462.223560] ---[ end trace 676638a3a12c7a56 ]---
Reported-by: Ralph Sennhauser <ralph.sennhauser@gmail.com>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Fixes: 0f247626cb
("usb: core: Introduce a USB port LED trigger")
Cc: stable@vger.kernel.org # 4.9+
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
314 lines
7.6 KiB
C
314 lines
7.6 KiB
C
/*
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* USB port LED trigger
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*
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* Copyright (C) 2016 Rafał Miłecki <rafal@milecki.pl>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*/
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#include <linux/device.h>
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#include <linux/leds.h>
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/usb.h>
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struct usbport_trig_data {
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struct led_classdev *led_cdev;
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struct list_head ports;
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struct notifier_block nb;
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int count; /* Amount of connected matching devices */
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};
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struct usbport_trig_port {
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struct usbport_trig_data *data;
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struct usb_device *hub;
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int portnum;
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char *port_name;
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bool observed;
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struct device_attribute attr;
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struct list_head list;
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};
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/***************************************
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* Helpers
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***************************************/
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/**
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* usbport_trig_usb_dev_observed - Check if dev is connected to observed port
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*/
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static bool usbport_trig_usb_dev_observed(struct usbport_trig_data *usbport_data,
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struct usb_device *usb_dev)
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{
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struct usbport_trig_port *port;
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if (!usb_dev->parent)
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return false;
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list_for_each_entry(port, &usbport_data->ports, list) {
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if (usb_dev->parent == port->hub &&
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usb_dev->portnum == port->portnum)
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return port->observed;
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}
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return false;
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}
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static int usbport_trig_usb_dev_check(struct usb_device *usb_dev, void *data)
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{
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struct usbport_trig_data *usbport_data = data;
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if (usbport_trig_usb_dev_observed(usbport_data, usb_dev))
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usbport_data->count++;
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return 0;
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}
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/**
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* usbport_trig_update_count - Recalculate amount of connected matching devices
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*/
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static void usbport_trig_update_count(struct usbport_trig_data *usbport_data)
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{
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struct led_classdev *led_cdev = usbport_data->led_cdev;
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usbport_data->count = 0;
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usb_for_each_dev(usbport_data, usbport_trig_usb_dev_check);
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led_set_brightness(led_cdev, usbport_data->count ? LED_FULL : LED_OFF);
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}
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/***************************************
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* Device attr
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***************************************/
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static ssize_t usbport_trig_port_show(struct device *dev,
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struct device_attribute *attr, char *buf)
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{
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struct usbport_trig_port *port = container_of(attr,
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struct usbport_trig_port,
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attr);
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return sprintf(buf, "%d\n", port->observed) + 1;
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}
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static ssize_t usbport_trig_port_store(struct device *dev,
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struct device_attribute *attr,
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const char *buf, size_t size)
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{
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struct usbport_trig_port *port = container_of(attr,
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struct usbport_trig_port,
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attr);
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if (!strcmp(buf, "0") || !strcmp(buf, "0\n"))
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port->observed = 0;
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else if (!strcmp(buf, "1") || !strcmp(buf, "1\n"))
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port->observed = 1;
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else
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return -EINVAL;
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usbport_trig_update_count(port->data);
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return size;
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}
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static struct attribute *ports_attrs[] = {
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NULL,
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};
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static const struct attribute_group ports_group = {
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.name = "ports",
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.attrs = ports_attrs,
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};
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/***************************************
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* Adding & removing ports
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***************************************/
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static int usbport_trig_add_port(struct usbport_trig_data *usbport_data,
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struct usb_device *usb_dev,
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const char *hub_name, int portnum)
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{
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struct led_classdev *led_cdev = usbport_data->led_cdev;
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struct usbport_trig_port *port;
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size_t len;
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int err;
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port = kzalloc(sizeof(*port), GFP_KERNEL);
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if (!port) {
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err = -ENOMEM;
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goto err_out;
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}
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port->data = usbport_data;
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port->hub = usb_dev;
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port->portnum = portnum;
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len = strlen(hub_name) + 8;
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port->port_name = kzalloc(len, GFP_KERNEL);
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if (!port->port_name) {
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err = -ENOMEM;
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goto err_free_port;
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}
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snprintf(port->port_name, len, "%s-port%d", hub_name, portnum);
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port->attr.attr.name = port->port_name;
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port->attr.attr.mode = S_IRUSR | S_IWUSR;
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port->attr.show = usbport_trig_port_show;
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port->attr.store = usbport_trig_port_store;
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err = sysfs_add_file_to_group(&led_cdev->dev->kobj, &port->attr.attr,
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ports_group.name);
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if (err)
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goto err_free_port_name;
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list_add_tail(&port->list, &usbport_data->ports);
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return 0;
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err_free_port_name:
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kfree(port->port_name);
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err_free_port:
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kfree(port);
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err_out:
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return err;
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}
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static int usbport_trig_add_usb_dev_ports(struct usb_device *usb_dev,
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void *data)
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{
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struct usbport_trig_data *usbport_data = data;
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int i;
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for (i = 1; i <= usb_dev->maxchild; i++)
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usbport_trig_add_port(usbport_data, usb_dev,
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dev_name(&usb_dev->dev), i);
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return 0;
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}
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static void usbport_trig_remove_port(struct usbport_trig_data *usbport_data,
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struct usbport_trig_port *port)
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{
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struct led_classdev *led_cdev = usbport_data->led_cdev;
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list_del(&port->list);
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sysfs_remove_file_from_group(&led_cdev->dev->kobj, &port->attr.attr,
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ports_group.name);
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kfree(port->port_name);
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kfree(port);
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}
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static void usbport_trig_remove_usb_dev_ports(struct usbport_trig_data *usbport_data,
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struct usb_device *usb_dev)
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{
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struct usbport_trig_port *port, *tmp;
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list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) {
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if (port->hub == usb_dev)
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usbport_trig_remove_port(usbport_data, port);
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}
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}
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/***************************************
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* Init, exit, etc.
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***************************************/
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static int usbport_trig_notify(struct notifier_block *nb, unsigned long action,
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void *data)
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{
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struct usbport_trig_data *usbport_data =
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container_of(nb, struct usbport_trig_data, nb);
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struct led_classdev *led_cdev = usbport_data->led_cdev;
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struct usb_device *usb_dev = data;
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bool observed;
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observed = usbport_trig_usb_dev_observed(usbport_data, usb_dev);
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switch (action) {
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case USB_DEVICE_ADD:
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usbport_trig_add_usb_dev_ports(usb_dev, usbport_data);
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if (observed && usbport_data->count++ == 0)
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led_set_brightness(led_cdev, LED_FULL);
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return NOTIFY_OK;
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case USB_DEVICE_REMOVE:
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usbport_trig_remove_usb_dev_ports(usbport_data, usb_dev);
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if (observed && --usbport_data->count == 0)
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led_set_brightness(led_cdev, LED_OFF);
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return NOTIFY_OK;
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}
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return NOTIFY_DONE;
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}
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static void usbport_trig_activate(struct led_classdev *led_cdev)
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{
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struct usbport_trig_data *usbport_data;
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int err;
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usbport_data = kzalloc(sizeof(*usbport_data), GFP_KERNEL);
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if (!usbport_data)
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return;
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usbport_data->led_cdev = led_cdev;
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/* List of ports */
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INIT_LIST_HEAD(&usbport_data->ports);
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err = sysfs_create_group(&led_cdev->dev->kobj, &ports_group);
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if (err)
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goto err_free;
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usb_for_each_dev(usbport_data, usbport_trig_add_usb_dev_ports);
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/* Notifications */
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usbport_data->nb.notifier_call = usbport_trig_notify,
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led_cdev->trigger_data = usbport_data;
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usb_register_notify(&usbport_data->nb);
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led_cdev->activated = true;
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return;
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err_free:
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kfree(usbport_data);
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}
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static void usbport_trig_deactivate(struct led_classdev *led_cdev)
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{
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struct usbport_trig_data *usbport_data = led_cdev->trigger_data;
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struct usbport_trig_port *port, *tmp;
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if (!led_cdev->activated)
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return;
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list_for_each_entry_safe(port, tmp, &usbport_data->ports, list) {
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usbport_trig_remove_port(usbport_data, port);
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}
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usb_unregister_notify(&usbport_data->nb);
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sysfs_remove_group(&led_cdev->dev->kobj, &ports_group);
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kfree(usbport_data);
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led_cdev->activated = false;
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}
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static struct led_trigger usbport_led_trigger = {
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.name = "usbport",
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.activate = usbport_trig_activate,
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.deactivate = usbport_trig_deactivate,
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};
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static int __init usbport_trig_init(void)
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{
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return led_trigger_register(&usbport_led_trigger);
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}
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static void __exit usbport_trig_exit(void)
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{
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led_trigger_unregister(&usbport_led_trigger);
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}
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module_init(usbport_trig_init);
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module_exit(usbport_trig_exit);
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MODULE_AUTHOR("Rafał Miłecki <rafal@milecki.pl>");
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MODULE_DESCRIPTION("USB port trigger");
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MODULE_LICENSE("GPL v2");
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