From: Felipe Balbi <balbi@kernel.org>
To: Janusz Dziedzic <janusz.dziedzic@gmail.com>,
Baolin Wang <baolin.wang@linaro.org>
Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org, linaro-kernel@lists.linaro.org,
broonie@kernel.org
Subject: Re: [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt handler and irq thread handler
Date: Tue, 27 Dec 2016 13:07:25 +0200 [thread overview]
Message-ID: <871swt3a1e.fsf@linux.intel.com> (raw)
In-Reply-To: <CAFED-j=mo2kSc8VBzgw6F9up3Dp8LB79dFAcAr+4baZ18jbXMQ@mail.gmail.com>
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Hi,
Janusz Dziedzic <janusz.dziedzic@gmail.com> writes:
> 2016-12-26 9:01 GMT+01:00 Baolin Wang <baolin.wang@linaro.org>:
>> On some platfroms(like x86 platform), when one core is running the USB gadget
>> irq thread handler by dwc3_thread_interrupt(), meanwhile another core also can
>> respond other interrupts from dwc3 controller and modify the event buffer by
>> dwc3_interrupt() function, that will cause getting the wrong event count in
>> irq thread handler to make the USB function abnormal.
>>
>> We should add spin_lock/unlock() in dwc3_check_event_buf() to avoid this race.
>>
> Interesting, I always think we mask interrupt in dwc3_interrupt() by setting
> DWC3_GEVNTSIZ_INTMASK
> And unmask interrupt when we end dwc3_thread_interrupt().
>
> So, we shouldn't get any IRQ from HW during dwc3_thread_interrupt(),
> or I miss something?
> Do you have some traces that indicate this masking will not work correctly?
that's the very question I have. We are already masking interrupts from
this controller. The only thing this could race with is usb_ep_queue(),
but that gets nowhere close to anything we're doing in the top half
handler, so there's really no danger of anything bad happening.
I'd like to see traces as well.
--
balbi
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prev parent reply other threads:[~2016-12-27 11:09 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-26 8:01 [PATCH] usb: dwc3: gadget: Avoid race between dwc3 interrupt handler and irq thread handler Baolin Wang
2016-12-27 2:39 ` Lu Baolu
2016-12-27 2:58 ` Baolin Wang
2016-12-27 4:45 ` Lu Baolu
2016-12-27 11:05 ` Felipe Balbi
2016-12-28 15:27 ` Janusz Dziedzic
2016-12-28 16:19 ` Felipe Balbi
2016-12-29 1:29 ` John Youn
2017-01-05 19:08 ` John Youn
2017-01-06 2:44 ` Baolin Wang
2016-12-27 10:52 ` Janusz Dziedzic
2016-12-27 11:06 ` Baolin Wang
2016-12-27 11:11 ` Felipe Balbi
2016-12-27 12:16 ` Baolin Wang
2016-12-28 12:30 ` Janusz Dziedzic
2017-01-03 12:21 ` Baolin Wang
2017-01-03 12:33 ` Felipe Balbi
2017-01-05 2:07 ` Baolin Wang
2017-01-05 9:26 ` Felipe Balbi
2017-01-05 9:43 ` Baolin Wang
2017-01-05 11:19 ` Felipe Balbi
2017-01-05 12:03 ` Baolin Wang
2016-12-27 11:07 ` Felipe Balbi [this message]
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