From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D76C2207E04; Wed, 19 Mar 2025 01:27:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742347675; cv=none; b=o4bRUmlT1975AMYe5pSaOIqSePeEaIR2A5oJ9HWj72HLOZhE6oJbYBWWwR/vBOuxwSsls79JMI8RYoVUXGiwv9oJ6WjBSKWAFiqwzSGTQRmzMOyim2TR+8THZt5cfQWuz7Zf3j2kB5omOK6rD3Ja/POz3OAEEFMNCkeDGXeznKE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742347675; c=relaxed/simple; bh=CuVaPYVmTxG9Z/4/GY8XJLK4/KQ794QljAoN47lFzjI=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TpsrxvIz8PLUnjCkBCFY8A3Fr3hF7L30CJOgGpx5xoz9n9touqrm66Gz+mS3nfdOIiYer1cr64M7BmgiBzLSCBS/GgeLjFdTauhNoMwKGNdtvvri0yumHqbKh4w7VxBfWNC9m/RkI3Qy2aq8DT2z6HL8nK1l0FXnM4H6ER0do2c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UaLE5S/4; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UaLE5S/4" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1C169C4CEE3; Wed, 19 Mar 2025 01:27:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742347674; bh=CuVaPYVmTxG9Z/4/GY8XJLK4/KQ794QljAoN47lFzjI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=UaLE5S/4qIpbLqkK+uTylbL9aZ26EtlwM/+7mnRprz2E8Pi3JWsAXRg4QbCu0orKs SVTSDjbX9ZE+yFitzbzo9ZCY+XJyu4ncJxN02+NDCcFf6bWmk2cW9Df87WdjD1lEYY SJlTJUYUB/ntzlEHmSuGEtUw+vNsnibebqwjGya3h8ucocZwxVYdC9PZzqSjYqmW+c Kw/XxQ/vCseqQYEvkokYtSJ8TNyQ4ujvQV4ckDoCY9OqVGkYi3NMXqqVAhI5DIgyJa Avz0g7TrjSOPSm0DLFMWqvRtJsEdI5d8KUiH43ootRqKpNxoTiBaLAFIC2y9AX6AoF EkQCyki6IB/4A== Date: Wed, 19 Mar 2025 09:27:47 +0800 From: "Peter Chen (CIX)" To: Ralph Siemsen Cc: Sebastian Andrzej Siewior , Pawel Laszczak , Roger Quadros , Aswath Govindraju , Greg Kroah-Hartman , Felipe Balbi , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev, Thomas Gleixner , Steven Rostedt , stable@vger.kernel.org Subject: Re: [PATCH v2] usb: cdns3: Fix deadlock when using NCM gadget Message-ID: References: <20250318-rfs-cdns3-deadlock-v2-1-bfd9cfcee732@linaro.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250318-rfs-cdns3-deadlock-v2-1-bfd9cfcee732@linaro.org> On 25-03-18 11:09:32, Ralph Siemsen wrote: > The cdns3 driver has the same NCM deadlock as fixed in cdnsp by commit > 58f2fcb3a845 ("usb: cdnsp: Fix deadlock issue during using NCM gadget"). > > Under PREEMPT_RT the deadlock can be readily triggered by heavy network > traffic, for example using "iperf --bidir" over NCM ethernet link. > > The deadlock occurs because the threaded interrupt handler gets > preempted by a softirq, but both are protected by the same spinlock. > Prevent deadlock by disabling softirq during threaded irq handler. > > cc: stable@vger.kernel.org > Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver") > Signed-off-by: Ralph Siemsen Acked-by: Peter Chen > --- > v2 changes: > - move the fix up the call stack, as per discussion at > https://lore.kernel.org/linux-rt-devel/20250226082931.-XRIDa6D@linutronix.de/ > --- > drivers/usb/cdns3/cdns3-gadget.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c > index fd1beb10bba72..19101ff1cf1bd 100644 > --- a/drivers/usb/cdns3/cdns3-gadget.c > +++ b/drivers/usb/cdns3/cdns3-gadget.c > @@ -1963,6 +1963,7 @@ static irqreturn_t cdns3_device_thread_irq_handler(int irq, void *data) > unsigned int bit; > unsigned long reg; > > + local_bh_disable(); > spin_lock_irqsave(&priv_dev->lock, flags); > > reg = readl(&priv_dev->regs->usb_ists); > @@ -2004,6 +2005,7 @@ static irqreturn_t cdns3_device_thread_irq_handler(int irq, void *data) > irqend: > writel(~0, &priv_dev->regs->ep_ien); > spin_unlock_irqrestore(&priv_dev->lock, flags); > + local_bh_enable(); > > return ret; > } > > --- > base-commit: 4701f33a10702d5fc577c32434eb62adde0a1ae1 > change-id: 20250312-rfs-cdns3-deadlock-697df5cad3ce > > Best regards, > -- > Ralph Siemsen > -- Best regards, Peter