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@xxxxxxxxxxxxxxx>
Cc: Wesley Cheng <quic_wcheng@xxxxxxxxxxx>
Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
---
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]);
--
2.39.2
