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From: Phil Elwell <phil@raspberrypi.com>
To: Mathias Nyman <mathias.nyman@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Jonathan Bell <jonathan@raspberrypi.com>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] xhci: guard accesses to ep_state in xhci_endpoint_reset()
Date: Tue, 31 Aug 2021 17:02:59 +0100	[thread overview]
Message-ID: <20210831160259.2392459-1-phil@raspberrypi.com> (raw)

From: Jonathan Bell <jonathan@raspberrypi.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@raspberrypi.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


             reply	other threads:[~2021-08-31 16:03 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-31 16:02 Phil Elwell [this message]
2021-09-01  9:21 ` [PATCH] xhci: guard accesses to ep_state in xhci_endpoint_reset() Mathias Nyman
2021-09-01 13:15   ` Phil Elwell
2021-09-01 18:51     ` Jonathan Bell

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