From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754753AbbJNW6v (ORCPT ); Wed, 14 Oct 2015 18:58:51 -0400 Received: from mail-pa0-f48.google.com ([209.85.220.48]:34674 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754159AbbJNW6t (ORCPT ); Wed, 14 Oct 2015 18:58:49 -0400 From: Douglas Anderson To: John Youn , balbi@ti.com Cc: Yunzhi Li , =?UTF-8?q?Heiko=20St=C3=BCbner?= , linux-rockchip@lists.infradead.org, Julius Werner , gregory.herrero@intel.com, yousaf.kaukab@intel.com, dinguyen@opensource.altera.com, Douglas Anderson , johnyoun@synopsys.com, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] usb: dwc2: host: Protect PCGCTL with lock in dwc2_port_resume() Date: Wed, 14 Oct 2015 15:58:27 -0700 Message-Id: <1444863507-27463-1-git-send-email-dianders@chromium.org> X-Mailer: git-send-email 2.6.0.rc2.230.g3dd15c0 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>From code inspection, it appears to be unsafe to do a read-modify-write of PCGCTL in dwc2_port_resume(). Let's make sure the spinlock is held around this operation. Signed-off-by: Douglas Anderson --- drivers/usb/dwc2/hcd.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c index af4e4a2..e79baf7 100644 --- a/drivers/usb/dwc2/hcd.c +++ b/drivers/usb/dwc2/hcd.c @@ -1500,6 +1500,8 @@ static void dwc2_port_resume(struct dwc2_hsotg *hsotg) u32 hprt0; u32 pcgctl; + spin_lock_irqsave(&hsotg->lock, flags); + /* * If hibernation is supported, Phy clock is already resumed * after registers restore. @@ -1508,10 +1510,11 @@ static void dwc2_port_resume(struct dwc2_hsotg *hsotg) pcgctl = dwc2_readl(hsotg->regs + PCGCTL); pcgctl &= ~PCGCTL_STOPPCLK; dwc2_writel(pcgctl, hsotg->regs + PCGCTL); + spin_unlock_irqrestore(&hsotg->lock, flags); usleep_range(20000, 40000); + spin_lock_irqsave(&hsotg->lock, flags); } - spin_lock_irqsave(&hsotg->lock, flags); hprt0 = dwc2_read_hprt0(hsotg); hprt0 |= HPRT0_RES; hprt0 &= ~HPRT0_SUSP; -- 2.6.0.rc2.230.g3dd15c0