linux-kernel - Re: [linux-next][PATCH] usb: dwc3: omap: remove IRQ

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]

Date:   Mon, 3 Jul 2017 13:28:37 -0500
From:   Grygorii Strashko <grygorii.strashko@...com>
To:     Vignesh R <vigneshr@...com>, Tony Lindgren <tony@...mide.com>
CC:     "GregKroah-Hartmangregkh@...uxfoundation.org" 
        <GregKroah-Hartmangregkh@...uxfoundation.org>,
        Felipe Balbi <balbi@...nel.org>,
        "linux-omap@...r.kernel.org" <linux-omap@...r.kernel.org>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "Nori, Sekhar" <nsekhar@...com>
Subject: Re: [linux-next][PATCH] usb: dwc3: omap: remove IRQ_NOAUTOEN used
 with shared irq



On 07/02/2017 11:27 PM, Vignesh R wrote:
> Hi,
> 
> On Saturday 01 July 2017 01:04 AM, Strashko, Grygorii wrote:
>>
>>
>> On 06/29/2017 01:03 AM, Tony Lindgren wrote:
>>> * Vignesh R <vigneshr@...com> [170628 21:21]:
>>>>
>>>>
>>>> On Thursday 29 June 2017 05:01 AM, Strashko, Grygorii wrote:
>>>>> IRQ_NOAUTOEN can't be used with shared IRQs and Kernel now will triggers
>>>>> warning if it happns, since commit 04c848d39879 ("genirq: Warn when
>>>>> IRQ_NOAUTOEN is used with shared interrupts"). And this is the case for
>>>>> OMAP DWC 3 driver.
>>>>>
>>>>> Hence, remove IRQ_NOAUTOEN flag and instead call disable_irq() before
>>>>> disabling PM runtime in probe error path handling.
>>>>
>>>> Or, how about requesting the irq at the end of probe after extcon
>>>> registration?
>>>
>>> Hmm yeah, what prevents the issue that we tried to fix with commit
>>> 12a7f17fac5b ("usb: dwc3: omap: fix race of pm runtime with irq handler
>>> in probe")?
>>
>> No, I think. There should be the disable_irq() call any way
>> before pm_runtime_put_sync(dev);| pm_runtime_disable(dev); -
>> once IRQ is requested driver can't know if IRQ handler is running now or not
>> unless it will call disable_irq()/free_irq().
>>
>> But, I've also thought about moving request_irq() down (seems
>> it can be moved even after of_platform_populate()).
>> looks like it can be separate patch.
>>
> 
> commit 12a7f17fac5b says PM runtime can race with IRQ handler when
> deferred probing happening due to extcon, therefore IRQ_NOAUTOEN was set
> and disable_irq() call was added. If IRQ handler registration is moved
> to a place after of_platform_populate(), then we can be sure that extcon
> is registered and there wont be any deferred probe or race with irq
> handler and PM runtime. Would disable_irq() still be needed then?
> 

You might be correct, so feel free to send a patch.

-- 
regards,
-grygorii