Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755263AbcLZIBj (ORCPT ); Mon, 26 Dec 2016 03:01:39 -0500 Received: from mail-pg0-f54.google.com ([74.125.83.54]:36059 "EHLO mail-pg0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752016AbcLZIBh (ORCPT ); Mon, 26 Dec 2016 03:01:37 -0500 From: Baolin Wang To: balbi@kernel.org, gregkh@linuxfoundation.org Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org, broonie@kernel.org, baolin.wang@linaro.org Subject: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt handler and irq thread handler Date: Mon, 26 Dec 2016 16:01:10 +0800 Message-Id: <0d79eb1f34e409749a136173b68f365b545c4789.1482738764.git.baolin.wang@linaro.org> X-Mailer: git-send-email 1.7.9.5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1396 Lines: 42 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 --- 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