[PATCH 5.14 041/151] xhci: guard accesses to ep_state in xhci_endpoint_reset()

Greg Kroah-Hartman
2021-10-18T13:52:27Z

From: Jonathan Bell <jonathan@raspberrypi.com>

commit a01ba2a3378be85538e0183ae5367c1bc1d5aaf3 upstream.

See https://github.com/raspberrypi/linux/issues/3981

Two read-modify-write cycles on ep->ep_state are not guarded by
xhci->lock. Fix these.

Fixes: f5249461b504 ("xhci: Clear the host side toggle manually when endpoint is soft reset")
Cc: stable@vger.kernel.org
Signed-off-by: Jonathan Bell <jonathan@raspberrypi.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20211008092547.3996295-2-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/host/xhci.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3212,10 +3212,13 @@ static void xhci_endpoint_reset(struct u
return;

/* Bail out if toggle is already being cleared by a endpoint reset */
+ spin_lock_irqsave(&xhci->lock, flags);
if (ep->ep_state & EP_HARD_CLEAR_TOGGLE) {
ep->ep_state &= ~EP_HARD_CLEAR_TOGGLE;
+ spin_unlock_irqrestore(&xhci->lock, flags);
return;
}
+ spin_unlock_irqrestore(&xhci->lock, flags);
/* Only interrupt and bulk ep's use data toggle, USB2 spec 5.5.4-> */
if (usb_endpoint_xfer_control(&host_ep->desc) ||
usb_endpoint_xfer_isoc(&host_ep->desc))
@@ -3301,8 +3304,10 @@ static void xhci_endpoint_reset(struct u
xhci_free_command(xhci, cfg_cmd);
cleanup:
xhci_free_command(xhci, stop_cmd);
+ spin_lock_irqsave(&xhci->lock, flags);
if (ep->ep_state & EP_SOFT_CLEAR_TOGGLE)
ep->ep_state &= ~EP_SOFT_CLEAR_TOGGLE;
+ spin_unlock_irqrestore(&xhci->lock, flags);
}

static int xhci_check_streams_endpoint(struct xhci_hcd *xhci,