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From 9d51ba9909129465493d56a7134ce4220d2e69e9 Mon Sep 17 00:00:00 2001
From: Jonathan Bell <jonathan@raspberrypi.com>
Date: Mon, 16 Aug 2021 14:43:06 +0100
Subject: [PATCH] xhci: guard accesses to ep_state in
xhci_endpoint_reset()
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(+)
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -3270,10 +3270,13 @@ 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))
@@ -3359,8 +3362,10 @@ 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,
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