patch "usbip:vudc: BUG kmalloc-2048 (Not tainted): Poison overwritten" added to usb-testing

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

usbip:vudc: BUG kmalloc-2048 (Not tainted): Poison overwritten

to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-testing branch.

The patch will show up in the next release of the linux-next tree (usually sometime within the next 24 hours during the week.)

The patch will be merged to the usb-next branch sometime soon, after it passes testing, and the merge window is open.

If you have any questions about this process, please let me know.

From: "Shuah Khan (Samsung OSG)" <[email protected]>
Date: Thu, 18 Oct 2018 10:19:29 -0600
Subject: usbip:vudc: BUG kmalloc-2048 (Not tainted): Poison overwritten

In rmmod path, usbip_vudc does platform_device_put() twice once from platform_device_unregister() and then from put_vudc_device().

The second put results in:

BUG kmalloc-2048 (Not tainted): Poison overwritten error or

BUG: KASAN: use-after-free in kobject_put+0x1e/0x230 if KASAN is

enabled.

[  169.042156] calling  init+0x0/0x1000 [usbip_vudc] @ 1697
[  169.042396] =============================================================================
[  169.043678] probe of usbip-vudc.0 returned 1 after 350 usecs
[  169.044508] BUG kmalloc-2048 (Not tainted): Poison overwritten
[  169.044509] -----------------------------------------------------------------------------
...
[  169.057849] INFO: Freed in device_release+0x2b/0x80 age=4223 cpu=3 pid=1693
[  169.057852] 	kobject_put+0x86/0x1b0
[  169.057853] 	0xffffffffc0c30a96
[  169.057855] 	__x64_sys_delete_module+0x157/0x240

Fix it to call platform_device_del() instead and let put_vudc_device() do the platform_device_put().

---
 drivers/usb/usbip/vudc_main.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

index 3fc22037a82f..390733e6937e 100644
@@ -73,6 +73,10 @@ static int __init init(void)
 cleanup:
 	list_for_each_entry_safe(udc_dev, udc_dev2, &vudc_devices, dev_entry) {
 		list_del(&udc_dev->dev_entry);
+		/*
+		 * Just do platform_device_del() here, put_vudc_device()
+		 * calls the platform_device_put()
+		 */
 		platform_device_del(udc_dev->pdev);
 		put_vudc_device(udc_dev);
 	}

@@ -89,7 +93,11 @@ static void __exit cleanup(void)
 
 	list_for_each_entry_safe(udc_dev, udc_dev2, &vudc_devices, dev_entry) {
 		list_del(&udc_dev->dev_entry);
-		platform_device_unregister(udc_dev->pdev);
+		/*
+		 * Just do platform_device_del() here, put_vudc_device()
+		 * calls the platform_device_put()
+		 */
+		platform_device_del(udc_dev->pdev);
 		put_vudc_device(udc_dev);
 	}
 	platform_driver_unregister(&vudc_driver);

2.19.1