Messages in this thread | | | Date | Wed, 22 May 2013 16:26:20 +0300 | Subject | Re: [PATCH] dmatest: abort transfers immediately when asked for | From | Andy Shevchenko <> |
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On Wed, May 22, 2013 at 3:41 PM, Will Deacon <will.deacon@arm.com> wrote: > On Tue, May 21, 2013 at 06:24:15PM +0100, Andy Shevchenko wrote: >> On Tue, May 21, 2013 at 6:11 PM, Will Deacon <will.deacon@arm.com> wrote: >> > I now observe buffer verification failures in subsequent >> > test runs after an aborted run: >> >> I think the description to the commit adfa543e "dmatest: don't use >> set_freezable_with_signal()" may shed light on this. >> >> The background (if I got it correctly) is in race with done flag. So, >> we got a callback call from the DMA engine, but we don't know which >> transfer triggers it. >> I might be wrong. This is just an assumption. > > I've not managed to work out exactly what's going on, but it's certainly > something like that. In fact, I just managed to trigger a case where all but > one of the transfers is aborted, whilst the remaining one fails. Looking at > the code, I can't see how that situation comes about, since the threads are > protected with the info mutex and kthread_stop is synchronous.
>> Have you ever see such behaviour on pre v3.10-rc1 kernels? (I mean >> with old dmatest module) > > No, dmatest from 3.9 is completely reliable in my experience.
Yeah, I supposed that was a rhetorical question.
So, have I understood correctly that if you revert the 77101ce5 ("cancel thread ...") everything is working fine / as before?
-- With Best Regards, Andy Shevchenko
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