linux-kernel - Re: [PATCH 1/2] usb: gadget: r8a66597: Fix two possible sleep-in-atomic-context bugs in init

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Message-ID: <87y3eydrs1.fsf@linux.intel.com>
Date:   Fri, 29 Jun 2018 09:35:10 +0300
From:   Felipe Balbi <balbi@...nel.org>
To:     Robert Jarzmik <robert.jarzmik@...e.fr>,
        Jia-Ju Bai <baijiaju1990@...il.com>
Cc:     gregkh@...uxfoundation.org, nicolas.ferre@...rochip.com,
        keescook@...omium.org, allen.lkml@...il.com,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] usb: gadget: r8a66597: Fix two possible sleep-in-atomic-context bugs in init_controller()


Hi,

Robert Jarzmik <robert.jarzmik@...e.fr> writes:

> Jia-Ju Bai <baijiaju1990@...il.com> writes:
>
>> The driver may sleep with holding a spinlock.
>> The function call paths (from bottom to top) in Linux-4.16.7 are:
>>
>> [FUNC] msleep
>> drivers/usb/gadget/udc/r8a66597-udc.c, 839: 
>> 		msleep in init_controller
>> drivers/usb/gadget/udc/r8a66597-udc.c, 96: 
>> 		init_controller in r8a66597_usb_disconnect
>> drivers/usb/gadget/udc/r8a66597-udc.c, 93: 
>> 		spin_lock in r8a66597_usb_disconnect
>
> That should not happen...
>
> If think the issue you have is that your usb_connect() and usb_disconnect() are
> called from interrupt context. I think the proper fix, as what is done in most
> udc phys, is to schedule a workqueue, see drivers/usb/phy/phy-gpio-vbus-usb.c,
> gpio_vbus_data.vbus.

argh, no. No workqueues needed here. Sorry

-- 
balbi