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

[<gregkh@linuxfoundation.org>]

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-next 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 also be merged in the next major kernel release
during the merge window.

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


>From e28fd56ad5273be67d0fae5bedc7e1680e729952 Mon Sep 17 00:00:00 2001
From: "Shuah Khan (Samsung OSG)" <shuah@kernel.org>
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().

Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Shuah Khan (Samsung OSG) <shuah@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/usb/usbip/vudc_main.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/usbip/vudc_main.c b/drivers/usb/usbip/vudc_main.c
index 3fc22037a82f..390733e6937e 100644
--- a/drivers/usb/usbip/vudc_main.c
+++ b/drivers/usb/usbip/vudc_main.c
@@ -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