Date:   Tue, 14 Dec 2021 19:37:21 +0800
From:   Peter Chen <peter.chen@kernel.org>
To:     Pawel Laszczak <pawell@cadence.com>
Cc:     gregkh@linuxfoundation.org, linux-usb@vger.kernel.org,
        linux-kernel@vger.kernel.org, jianhe@ambarella.com,
        stable@vger.kernel.org
Subject: Re: [PATCH v2] usb: cdnsp: Fix lack of
 spin_lock_irqsave/spin_lock_restore
Message-ID: <20211214113721.GA4527@Peter>
References: <20211214045527.26823-1-pawell@gli-login.cadence.com>
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On 21-12-14 05:55:27, Pawel Laszczak wrote:
> From: Pawel Laszczak <pawell@cadence.com>
> 
> Patch puts content of cdnsp_gadget_pullup function inside
> spin_lock_irqsave and spin_lock_restore section.
> This construction is required here to keep the data consistency,
> otherwise some data can be changed e.g. from interrupt context.
> 
> Fixes: 3d82904559f4 ("usb: cdnsp: cdns3 Add main part of Cadence USBSSP DRD Driver")
> Reported-by: Ken (Jian) He <jianhe@ambarella.com>
> cc: <stable@vger.kernel.org>
> Signed-off-by: Pawel Laszczak <pawell@cadence.com>

Reviewed-by: Peter Chen <peter.chen@kernel.org>

> --
> 
> Changelog:
> v2:
> - added disable_irq/enable_irq as sugester by Peter Chen
> 
>  drivers/usb/cdns3/cdnsp-gadget.c | 12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/usb/cdns3/cdnsp-gadget.c b/drivers/usb/cdns3/cdnsp-gadget.c
> index f6d231760a6a..e07a65b980af 100644
> --- a/drivers/usb/cdns3/cdnsp-gadget.c
> +++ b/drivers/usb/cdns3/cdnsp-gadget.c
> @@ -1544,15 +1544,27 @@ static int cdnsp_gadget_pullup(struct usb_gadget *gadget, int is_on)
>  {
>  	struct cdnsp_device *pdev = gadget_to_cdnsp(gadget);
>  	struct cdns *cdns = dev_get_drvdata(pdev->dev);
> +	unsigned long flags;
>  
>  	trace_cdnsp_pullup(is_on);
>  
> +	/*
> +	 * Disable events handling while controller is being
> +	 * enabled/disabled.
> +	 */
> +	disable_irq(cdns->dev_irq);
> +	spin_lock_irqsave(&pdev->lock, flags);
> +
>  	if (!is_on) {
>  		cdnsp_reset_device(pdev);
>  		cdns_clear_vbus(cdns);
>  	} else {
>  		cdns_set_vbus(cdns);
>  	}
> +
> +	spin_unlock_irqrestore(&pdev->lock, flags);
> +	enable_irq(cdns->dev_irq);
> +
>  	return 0;
>  }
>  
> -- 
> 2.25.1
> 

-- 

Thanks,
Peter Chen