In the Linux kernel, the following vulnerability has been resolved: usb: gadget: ffs: Fix epfile null pointer access after ep enable. A race condition occurs when ffsfuncepsenable() runs concurrently with ffsdatareset(). The ffsdataclear() called in ffsdatareset() sets ffs->epfiles to NULL before resetting ffs->epscount to 0, leading to a NULL pointer dereference when accessing epfile->ep in ffsfuncepsenable() after successful usbepenable(). The ffs->epfiles pointer is set to NULL in both ffsdataclear() and ffsdataclose() functions, and its modification is protected by the spinlock ffs->epslock. And the whole ffsfuncepsenable() function is also protected by ffs->epslock. Thus, add NULL pointer handling for ffs->epfiles in the ffsfuncepsenable() function to fix issues