From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id ADF43C4707E for ; Sat, 22 May 2021 09:54:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 899076128A for ; Sat, 22 May 2021 09:54:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230336AbhEVJ4E (ORCPT ); Sat, 22 May 2021 05:56:04 -0400 Received: from mail.kernel.org ([198.145.29.99]:50668 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230298AbhEVJ4E (ORCPT ); Sat, 22 May 2021 05:56:04 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 4091761261; Sat, 22 May 2021 09:54:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621677277; bh=1id7JO5kkP8rqGxR/9LR0zPSgXCJ1HO45UaR4koWk24=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=uRwPSQ5887CTttHF1I/VvjgC6VMMhzvJGcALODoMlUFJ3Csnhj0RyRb+g9NfCN4Y3 W++qIqR7i/1Nr3w3k+yIUmJ+35AfgW0NpjejkTIydJ6Xe/hUGSMzPatCs9aLM1SSIA dRwpir+8F9bi6wrTHrMw0CrJLMgCk64VOfU/YgwqSciYJzTVwh4lj/YIR+5VPrSP9f g6MgNqW8orHU40UTEGmvDUTAIEBkxha0T7W0VSkD2aMfUhGztX9pNvw0Qp81VwsUlS UJiyFKv34TwfbXqJ/DKvYrJ4vtWBtFKnSSR8NDrHKKjkBPc19tG626pwdlFeC5UlXX 6l2Mqo2Af4LnA== Date: Sat, 22 May 2021 17:54:32 +0800 From: Peter Chen To: Pawel Laszczak Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, kurahul@cadence.com, stable@vger.kernel.org Subject: Re: [PATCH] usb: cdnsp: Fix deadlock issue in cdnsp_thread_irq_handler Message-ID: <20210522095432.GA12415@b29397-desktop> References: <20210520094224.14099-1-pawell@gli-login.cadence.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210520094224.14099-1-pawell@gli-login.cadence.com> User-Agent: Mutt/1.9.4 (2018-02-28) Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org On 21-05-20 11:42:24, Pawel Laszczak wrote: > From: Pawel Laszczak > > Patch fixes the critical issue caused by deadlock which has been detected > during testing NCM class. > > The root cause of issue is spin_lock/spin_unlock instruction instead > spin_lock_irqsave/spin_lock_irqrestore in cdnsp_thread_irq_handler > function. Pawel, would you please explain more about why the deadlock occurs with current code, and why this patch could fix it? Peter > > Cc: stable@vger.kernel.org > Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver") > Signed-off-by: Pawel Laszczak > --- > drivers/usb/cdns3/cdnsp-ring.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/drivers/usb/cdns3/cdnsp-ring.c b/drivers/usb/cdns3/cdnsp-ring.c > index 5f0513c96c04..68972746e363 100644 > --- a/drivers/usb/cdns3/cdnsp-ring.c > +++ b/drivers/usb/cdns3/cdnsp-ring.c > @@ -1517,13 +1517,14 @@ irqreturn_t cdnsp_thread_irq_handler(int irq, void *data) > { > struct cdnsp_device *pdev = (struct cdnsp_device *)data; > union cdnsp_trb *event_ring_deq; > + unsigned long flags; > int counter = 0; > > - spin_lock(&pdev->lock); > + spin_lock_irqsave(&pdev->lock, flags); > > if (pdev->cdnsp_state & (CDNSP_STATE_HALTED | CDNSP_STATE_DYING)) { > cdnsp_died(pdev); > - spin_unlock(&pdev->lock); > + spin_unlock_irqrestore(&pdev->lock, flags); > return IRQ_HANDLED; > } > > @@ -1539,7 +1540,7 @@ irqreturn_t cdnsp_thread_irq_handler(int irq, void *data) > > cdnsp_update_erst_dequeue(pdev, event_ring_deq, 1); > > - spin_unlock(&pdev->lock); > + spin_unlock_irqrestore(&pdev->lock, flags); > > return IRQ_HANDLED; > } > -- > 2.25.1 > -- Thanks, Peter Chen