linux-kernel - Re: [PATCH 2/2] usb: dwc3: drd: Fix lock-up on ID change during system suspend/resume

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <8c4da216-7468-df31-01e3-644601421049@ti.com>
Date:   Wed, 24 Jan 2018 14:19:24 +0200
From:   Roger Quadros <rogerq@...com>
To:     Manu Gautam <mgautam@...eaurora.org>, <balbi@...nel.org>
CC:     <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/2] usb: dwc3: drd: Fix lock-up on ID change during
 system suspend/resume

On 23/01/18 14:41, Roger Quadros wrote:
> Hi Manu,
> 
> On 23/01/18 05:45, Manu Gautam wrote:
>> Hi,
>>
>>
>> On 1/22/2018 6:31 PM, Roger Quadros wrote:
>>> Adding/removing host/gadget controller before .pm_complete()
>>> causes a lock-up. Let's prevent any dual-role state change
>>> between .pm_prepare() and .pm_complete() to fix this.
>>
>> What kind of lock-up are you seeing? Some hardware lockup or software deadlock?
>> IMO using a freezable_wq for drd_work should address that?
>>
> 
> I was seeing a software deadlock. freezable_wq is a good idea. I'll try it out.

using freezable_wq doesn't get rid of the deadlock.
If I use freezable_wq plus add some delay before I do a dwc3_host_init()
in the work function then it starts to work.

As dependence on delay looks fragile so I'll stick to the current implementation
based on .pm_prepare/complete().

-- 
cheers,
-roger

Texas Instruments Finland Oy, Porkkalankatu 22, 00180 Helsinki. Y-tunnus/Business ID: 0615521-4. Kotipaikka/Domicile: Helsinki