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Groups > linux.kernel > #1547274

[PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt handler and irq thread handler

From Baolin Wang <baolin.wang@linaro.org>
Newsgroups linux.kernel
Subject [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt handler and irq thread handler
Date 2016-12-26 09:10 +0100
Message-ID <sSyw1-28c-1@gated-at.bofh.it> (permalink)
Organization linux.* mail to news gateway

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On some platfroms(like x86 platform), when one core is running the USB gadget
irq thread handler by dwc3_thread_interrupt(), meanwhile another core also can
respond other interrupts from dwc3 controller and modify the event buffer by
dwc3_interrupt() function, that will cause getting the wrong event count in
irq thread handler to make the USB function abnormal.

We should add spin_lock/unlock() in dwc3_check_event_buf() to avoid this race.

Signed-off-by: Baolin Wang <baolin.wang@linaro.org>
---
 drivers/usb/dwc3/gadget.c |    6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 6785595..1a1e1f4 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -2894,10 +2894,13 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt)
 		return IRQ_HANDLED;
 	}
 
+	spin_lock(&dwc->lock);
 	count = dwc3_readl(dwc->regs, DWC3_GEVNTCOUNT(0));
 	count &= DWC3_GEVNTCOUNT_MASK;
-	if (!count)
+	if (!count) {
+		spin_unlock(&dwc->lock);
 		return IRQ_NONE;
+	}
 
 	evt->count = count;
 	evt->flags |= DWC3_EVENT_PENDING;
@@ -2914,6 +2917,7 @@ static irqreturn_t dwc3_check_event_buf(struct dwc3_event_buffer *evt)
 		memcpy(evt->cache, evt->buf, count - amount);
 
 	dwc3_writel(dwc->regs, DWC3_GEVNTCOUNT(0), count);
+	spin_unlock(&dwc->lock);
 
 	return IRQ_WAKE_THREAD;
 }
-- 
1.7.9.5

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Thread

[PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt handler and irq thread handler Baolin Wang <baolin.wang@linaro.org> - 2016-12-26 09:10 +0100
  Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt  handler and irq thread handler Lu Baolu <baolu.lu@linux.intel.com> - 2016-12-27 03:50 +0100
    Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt  handler and irq thread handler Baolin Wang <baolin.wang@linaro.org> - 2016-12-27 04:00 +0100
      Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt  handler and irq thread handler Lu Baolu <baolu.lu@linux.intel.com> - 2016-12-27 05:50 +0100
    Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt handler and irq thread handler Felipe Balbi <balbi@kernel.org> - 2016-12-27 12:10 +0100
      Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt  handler and irq thread handler Janusz Dziedzic <janusz.dziedzic@gmail.com> - 2016-12-28 16:30 +0100
        Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt handler and irq thread handler Felipe Balbi <balbi@kernel.org> - 2016-12-28 17:30 +0100
          RE: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt  handler and irq thread handler John Youn <John.Youn@synopsys.com> - 2016-12-29 02:40 +0100
  Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt  handler and irq thread handler Janusz Dziedzic <janusz.dziedzic@gmail.com> - 2016-12-27 12:00 +0100
    Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt  handler and irq thread handler Baolin Wang <baolin.wang@linaro.org> - 2016-12-27 12:10 +0100
      Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt handler and irq thread handler Felipe Balbi <balbi@kernel.org> - 2016-12-27 12:20 +0100
        Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt  handler and irq thread handler Baolin Wang <baolin.wang@linaro.org> - 2016-12-27 13:20 +0100
          Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt  handler and irq thread handler Janusz Dziedzic <janusz.dziedzic@gmail.com> - 2016-12-28 13:40 +0100
            Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt  handler and irq thread handler Baolin Wang <baolin.wang@linaro.org> - 2017-01-03 13:30 +0100
              Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt handler and irq thread handler Felipe Balbi <balbi@kernel.org> - 2017-01-03 13:40 +0100
    Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt handler and irq thread handler Felipe Balbi <balbi@kernel.org> - 2016-12-27 12:10 +0100

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