Commit dd83dc12 authored by Mathias Nyman's avatar Mathias Nyman Committed by Greg Kroah-Hartman
Browse files

xhci: sideband: don't dereference freed ring when removing sideband endpoint 



xhci_sideband_remove_endpoint() incorrecly assumes that the endpoint is
running and has a valid transfer ring.

Lianqin reported a crash during suspend/wake-up stress testing, and
found the cause to be dereferencing a non-existing transfer ring
'ep->ring' during xhci_sideband_remove_endpoint().

The endpoint and its ring may be in unknown state if this function
is called after xHCI was reinitialized in resume (lost power), or if
device is being re-enumerated, disconnected or endpoint already dropped.

Fix this by both removing unnecessary ring access, and by checking
ep->ring exists before dereferencing it. Also make sure endpoint is
running before attempting to stop it.

Remove the xhci_initialize_ring_info() call during sideband endpoint
removal as is it only initializes ring structure enqueue, dequeue and
cycle state values to their starting values without changing actual
hardware enqueue, dequeue and cycle state. Leaving them out of sync
is worse than leaving it as it is. The endpoint will get freed in after
this in most usecases.

If the (audio) class driver want's to reuse the endpoint after offload
then it is up to the class driver to ensure endpoint is properly set up.

Reported-by: default avatar胡连勤 <hulianqin@vivo.com>
Closes: https://lore.kernel.org/linux-usb/TYUPR06MB6217B105B059A7730C4F6EC8D2B9A@TYUPR06MB6217.apcprd06.prod.outlook.com/


Tested-by: default avatar胡连勤 <hulianqin@vivo.com>
Fixes: de66754e ("xhci: sideband: add initial api to register a secondary interrupter entity")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Link: https://patch.msgid.link/20260115233758.364097-2-mathias.nyman@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 9fa015bd

drivers/usb/host/xhci-sideband.c

+0 −1
Original line number Diff line number Diff line
@@ -210,7 +210,6 @@ xhci_sideband_remove_endpoint(struct xhci_sideband *sb, 
		return -ENODEV;



	__xhci_sideband_remove_endpoint(sb, ep);

	xhci_initialize_ring_info(ep->ring);



	return 0;

}

drivers/usb/host/xhci.c

+12 −3
Original line number Diff line number Diff line
@@ -2898,16 +2898,25 @@ int xhci_stop_endpoint_sync(struct xhci_hcd *xhci, struct xhci_virt_ep *ep, int 
			    gfp_t gfp_flags)

{

	struct xhci_command *command;

	struct xhci_ep_ctx *ep_ctx;

	unsigned long flags;

	int ret;

	int ret = -ENODEV;



	command = xhci_alloc_command(xhci, true, gfp_flags);

	if (!command)

		return -ENOMEM;



	spin_lock_irqsave(&xhci->lock, flags);

	ret = xhci_queue_stop_endpoint(xhci, command, ep->vdev->slot_id,



	/* make sure endpoint exists and is running before stopping it */

	if (ep->ring) {

		ep_ctx = xhci_get_ep_ctx(xhci, ep->vdev->out_ctx, ep->ep_index);

		if (GET_EP_CTX_STATE(ep_ctx) == EP_STATE_RUNNING)

			ret = xhci_queue_stop_endpoint(xhci, command,

						       ep->vdev->slot_id,

						       ep->ep_index, suspend);

	}



	if (ret < 0) {

		spin_unlock_irqrestore(&xhci->lock, flags);

		goto out;