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usb: core: usbport: Use proper LED API to fix potential crash 

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>
This commit is contained in:
Rafał Miłecki 2016-12-06 00:39:33 +01:00 committed by Greg Kroah-Hartman
parent 71158c28eb
commit 89778ba335
1 changed files with 3 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

7
drivers/usb/core/ledtrig-usbport.c
View File

@ -74,8 +74,7 @@ static void usbport_trig_update_count(struct usbport_trig_data *usbport_data)
usbport_data->count = 0;
usb_for_each_dev(usbport_data, usbport_trig_usb_dev_check);
led_cdev->brightness_set(led_cdev,
usbport_data->count ? LED_FULL : LED_OFF);
led_set_brightness(led_cdev, usbport_data->count ? LED_FULL : LED_OFF);
}
/***************************************
@ -228,12 +227,12 @@ static int usbport_trig_notify(struct notifier_block *nb, unsigned long action,
case USB_DEVICE_ADD:
usbport_trig_add_usb_dev_ports(usb_dev, usbport_data);
if (observed && usbport_data->count++ == 0)
led_cdev->brightness_set(led_cdev, LED_FULL);
led_set_brightness(led_cdev, LED_FULL);
return NOTIFY_OK;
case USB_DEVICE_REMOVE:
usbport_trig_remove_usb_dev_ports(usbport_data, usb_dev);
if (observed && --usbport_data->count == 0)
led_cdev->brightness_set(led_cdev, LED_OFF);
led_set_brightness(led_cdev, LED_OFF);
return NOTIFY_OK;
}