Patch "usb: core: usbport: Use proper LED API to fix potential crash" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

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

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
usb-core-usbport-use-proper-led-api-to-fix-potential-crash.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <[email protected]>
Date: Tue, 6 Dec 2016 00:39:33 +0100
Subject: usb: core: usbport: Use proper LED API to fix potential crash
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Content-Type: text/plain; charset=UTF-8
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From: Rafał Miłecki <[email protected]>

commit 89778ba335e302a450932ce5b703c1ee6216e949 upstream.

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 ]---

---
 drivers/usb/core/ledtrig-usbport.c |    7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

@@ -74,8 +74,7 @@ static void usbport_trig_update_count(st
 
 	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 no
 	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;
 	}
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/usb-core-usbport-use-proper-led-api-to-fix-potential-crash.patch