On 10/18/18 9:19 AM, Shuah Khan (Samsung OSG) wrote:

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

and Tested-by: Randy Dunlap rdunlap@infradead.org

Thanks.

---

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);