From: Marc Zyngier maz@kernel.org

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.

Fixes: c99b38c41234 ("xhci: add support to allocate several interrupters") Cc: Mathias Nyman mathias.nyman@linux.intel.com Cc: Wesley Cheng quic_wcheng@quicinc.com Cc: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Marc Zyngier maz@kernel.org Cc: stable@vger.kernel.org # 6.8+ Signed-off-by: Mathias Nyman mathias.nyman@linux.intel.com --- drivers/usb/host/xhci-mem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c index d7654f475daf..937ce5fd5809 100644 --- a/drivers/usb/host/xhci-mem.c +++ b/drivers/usb/host/xhci-mem.c @@ -1872,7 +1872,7 @@ void xhci_mem_cleanup(struct xhci_hcd *xhci)

cancel_delayed_work_sync(&xhci->cmd_timer);

- for (i = 0; i < xhci->max_interrupters; i++) { + for (i = 0; xhci->interrupters && i < xhci->max_interrupters; i++) { if (xhci->interrupters[i]) { xhci_remove_interrupter(xhci, xhci->interrupters[i]); xhci_free_interrupter(xhci, xhci->interrupters[i]);