usb: xhci: Check for xhci->interrupters being allocated in xhci_mem_clearup()

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: usb: xhci: Check for xhci->interrupters being allocated in xhci_mem_clearup() If xhci_mem_init() fails, it calls into xhci_mem_cleanup() to mop up the damage. If it fails early enough, before xhci->interrupters is allocated but after xhci->max_interrupters has been set, which happens in most (all?) cases, things get uglier, as xhci_mem_cleanup() unconditionally derefences xhci->interrupters. With prejudice. Gate the interrupt freeing loop with a check on xhci->interrupters being non-NULL. Found while debugging a DMA allocation issue that led the XHCI driver on this exact path.

References

• https://git.kernel.org/stable/c/3efb29f6a78d4746f958c1ab6cd7981c5762f03b
• https://git.kernel.org/stable/c/770cacc75b0091ece17349195d72133912c1ca7c
• https://git.kernel.org/stable/c/dcdb52d948f3a17ccd3fce757d9bd981d7c32039