Commit 19002e93 authored by Mathias Nyman's avatar Mathias Nyman Committed by Yongqiang Liu
Browse files

xhci: Fix failure to give back some cached cancelled URBs. 

mainline inclusion
from mainline-v5.15-rc1
commit 94f33914
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/IACV8P
CVE: CVE-2024-40927

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=94f339147fc3eb9edef7ee4ef6e39c569c073753



--------------------------------

Only TDs with status TD_CLEARING_CACHE will be given back after
cache is cleared with a set TR deq command.

xhci_invalidate_cached_td() failed to set the TD_CLEARING_CACHE status
for some cancelled TDs as it assumed an endpoint only needs to clear the
TD it stopped on.

This isn't always true. For example with streams enabled an endpoint may
have several stream rings, each stopping on a different TDs.

Note that if an endpoint has several stream rings, the current code
will still only clear the cache of the stream pointed to by the last
cancelled TD in the cancel list.

This patch only focus on making sure all canceled TDs are given back,
avoiding hung task after device removal.
Another fix to solve clearing the caches of all stream rings with
cancelled TDs is needed, but not as urgent.

This issue was simultanously discovered and debugged by
by Tao Wang, with a slightly different fix proposal.

Fixes: 674f8438 ("xhci: split handling halted endpoints into two steps")
Cc: <stable@vger.kernel.org> #5.12
Reported-by: default avatarTao Wang <wat@codeaurora.org>
Signed-off-by: default avatarMathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20210820123503.2605901-4-mathias.nyman@linux.intel.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarYongqiang Liu <liuyongqiang13@huawei.com>
parent 3b30074a

drivers/usb/host/xhci-ring.c

+25 −15
Original line number Diff line number Diff line
@@ -1072,17 +1072,21 @@ static int xhci_invalidate_cancelled_tds(struct xhci_virt_ep *ep) 
					 td->urb->stream_id);

		hw_deq &= ~0xf;



		if (td->cancel_status == TD_HALTED) {

			cached_td = td;

		} else if (trb_in_td(xhci, td->start_seg, td->first_trb,

			      td->last_trb, hw_deq, false)) {

		if (td->cancel_status == TD_HALTED ||

		    trb_in_td(xhci, td->start_seg, td->first_trb, td->last_trb, hw_deq, false)) {

			switch (td->cancel_status) {

			case TD_CLEARED: /* TD is already no-op */

			case TD_CLEARING_CACHE: /* set TR deq command already queued */

				break;

			case TD_DIRTY: /* TD is cached, clear it */

			case TD_HALTED:

				td->cancel_status = TD_CLEARING_CACHE;

				if (cached_td)

					/* FIXME  stream case, several stopped rings */

					xhci_dbg(xhci,

						 "Move dq past stream %u URB %p instead of stream %u URB %p\n",

						 td->urb->stream_id, td->urb,

						 cached_td->urb->stream_id, cached_td->urb);

				cached_td = td;

				break;

			}
@@ -1091,18 +1095,24 @@ static int xhci_invalidate_cancelled_tds(struct xhci_virt_ep *ep) 
			td->cancel_status = TD_CLEARED;

		}

	}

	if (cached_td) {

		cached_td->cancel_status = TD_CLEARING_CACHE;



	/* If there's no need to move the dequeue pointer then we're done */

	if (!cached_td)

		return 0;



	err = xhci_move_dequeue_past_td(xhci, slot_id, ep->ep_index,

					cached_td->urb->stream_id,

					cached_td);

		/* Failed to move past cached td, try just setting it noop */

	if (err) {

			td_to_noop(xhci, ring, cached_td, false);

			cached_td->cancel_status = TD_CLEARED;

		/* Failed to move past cached td, just set cached TDs to no-op */

		list_for_each_entry_safe(td, tmp_td, &ep->cancelled_td_list, cancelled_td_list) {

			if (td->cancel_status != TD_CLEARING_CACHE)

				continue;

			xhci_dbg(xhci, "Failed to clear cancelled cached URB %p, mark clear anyway\n",

				 td->urb);

			td_to_noop(xhci, ring, td, false);

			td->cancel_status = TD_CLEARED;

		}

		cached_td = NULL;

	}

	return 0;

}