Re: kexec fails if OF_UNITTEST=y (was: Re: [PATCH v2] Removes OF_UNITTEST dependency on OF_DYNAMIC config symbol)

From: Rob Herring <robherring2@gmail.com>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gaurav Minocha <gaurav.minocha.os@gmail.com>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	Grant Likely <grant.likely@linaro.org>,
	Rob Herring <rob.herring@linaro.org>,
	"kexec@lists.infradead.org" <kexec@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: kexec fails if OF_UNITTEST=y (was: Re: [PATCH v2] Removes OF_UNITTEST dependency on OF_DYNAMIC config symbol)
Date: Mon, 16 Mar 2015 19:25:26 -0500	[thread overview]
Message-ID: <CAL_Jsq+y98uP_vxKzsCVVj7hoMeGQkLB1o54iqst+dNXJkcFoA@mail.gmail.com> (raw)
In-Reply-To: <CAMuHMdVb47ogpLe_4iSz-NAxdcASUZ2HzTpxh+ibjcdMtiO-tQ@mail.gmail.com>

On Mon, Mar 16, 2015 at 5:58 AM, Geert Uytterhoeven
<geert@linux-m68k.org> wrote:
> On Fri, Jan 23, 2015 at 2:03 PM, Geert Uytterhoeven
> <geert@linux-m68k.org> wrote:
>> On Sun, Jan 11, 2015 at 8:19 AM, Gaurav Minocha
>> <gaurav.minocha.os@gmail.com> wrote:
>>> This patch intends to remove the unittests dependency on
>>> the functions defined in dynamic.c. So, rather than calling
>>> of_attach_node defined in dynamic.c, minimal functionality
>>> required to attach a new node is re-defined in unittest.c.
>>> Also, now after executing the tests the test data is not
>>> removed from the device tree so there is no need to call
>>> of_detach_node.
>>
>> Could there be unwanted side effects of not removing the test data?
>
> Unfortunately I found a regression introduced by commit 3ce04b4a9fdc30b6
> ("Removes OF_UNITTEST dependency on OF_DYNAMIC config symbol").
>
> If the test data is still present, kexec (kexec-tools 2.0.7 released 24
> November 2014, 1:2.0.7-5 in Debian) fails with:
>
> unrecoverable error: short read
> from"/proc/device-tree//testcase-data/large-property-PAGE_SIZEx8"
>
> Granted, this is a bug in kexec-tools, but I'm reporting it anyway, as it is
> a kernel regression with existing userspace.
>
> I believe this bug was fixed in kexec-tools by commit d1932cd592e2a6aa
> ("kexec/fs2dt: Use slurp_file_len to avoid partial read of files"), but I
> haven't tested the fix yet.

Is OF_UNITTEST enabled by default in Debian or this is a custom
kernel? Perhaps we should require a command line option to actually
populate the test data and run the tests?

We just need more tests to slow down the boot enough people will not
enable them by default. ;)

Rob

>
> Gr{oetje,eeting}s,
>
>                         Geert
>
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
>
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                 -- Linus Torvalds
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