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Message-Id: <20210831160259.2392459-1-phil@raspberrypi.com>
Date: Tue, 31 Aug 2021 17:02:59 +0100
From: Phil Elwell <phil@...pberrypi.com>
To: Mathias Nyman <mathias.nyman@...el.com>,
Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
Jonathan Bell <jonathan@...pberrypi.com>,
linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] xhci: guard accesses to ep_state in xhci_endpoint_reset()
From: Jonathan Bell <jonathan@...pberrypi.com>
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.
Signed-off-by: Jonathan Bell <jonathan@...pberrypi.com>
---
drivers/usb/host/xhci.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index f3dabd02382c2..902f410874e8e 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3213,10 +3213,13 @@ static void xhci_endpoint_reset(struct usb_hcd *hcd,
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))
@@ -3302,8 +3305,10 @@ static void xhci_endpoint_reset(struct usb_hcd *hcd,
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,
--
2.25.1
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