[OE-core] [PATCHv2] wic: fix images build in parallel

Paul Barker pbarker at konsulko.com
Fri Jan 17 12:27:11 UTC 2020


On Fri, 17 Jan 2020 at 12:17, Paul Barker <pbarker at konsulko.com> wrote:
>
> On Fri, 17 Jan 2020 at 11:59, Maxim Uvarov <maxim.uvarov at linaro.org> wrote:
> >
> > On Fri, 17 Jan 2020 at 13:18, Paul Barker <pbarker at konsulko.com> wrote:
> > >
> > > On Mon, 13 Jan 2020 at 14:12, Maxim Uvarov <maxim.uvarov at linaro.org> wrote:
> > > >
> > > > On Mon, 13 Jan 2020 at 17:00, Paul Barker <pbarker at konsulko.com> wrote:
> > > > >
> > > > > On Mon, 13 Jan 2020 at 13:57, Maxim Uvarov <maxim.uvarov at linaro.org> wrote:
> > > > > >
> > > > > > On Mon, 13 Jan 2020 at 16:31, Paul Barker <pbarker at konsulko.com> wrote:
> > > > > > >
> > > > > > > On Mon, 13 Jan 2020 at 13:08, Maxim Uvarov <maxim.uvarov at linaro.org> wrote:
> > > > > > > >
> > > > > > > > OE wic plugins create temporary file with the index of the line
> > > > > > > > tmp file name. This causes race in case several builds run in time.
> > > > > > > > Add more entropy as timestamp to remove this race.
> > > > > > >
> > > > > > > How would two wic images to be built in parallel with the same work
> > > > > > > directory? To my understanding an image recipe only supports building
> > > > > > > a single wic image.
> > > > > > >
> > > > > > > Thanks,
> > > > > > > Paul
> > > > > >
> > > > > > bitbake image1 image2 image3
> > > > > > all images build .wics and use about the same files, like firmware.
> > > > > > Issue is similar to that:
> > > > > > https://www.yoctoproject.org/pipermail/yocto/2018-June/041373.html
> > > > >
> > > > > Each image has its own work directory though.
> > > > >
> > > > > I'll take a look in more detail later today or tomorrow, if wic is
> > > > > writing temporary files outside of the work directory then that's a
> > > > > bug and should be fixed.
> > > >
> > > > Thanks. I saw bug in rawcopy plugin. All other places were patched due
> > > > to the same code.  I guess then for rawcopy temp files are in
> > > > DEST_IMAGE_DIR (which is common) instead of WORKDIR.
> > >
> > > I can't see how these files can possibly collide across parallel image
> > > builds. In the lines you changed in your patch, cr_workdir passed in
> > > as an argument set to imager.workdir (in
> > > scripts/lib/wic/plugins/imager/direct.py) which is a temporary
> > > directory created under options.outdir. image_types_wic.bbclass passes
> > > the -o option to wic to set the outdir to something under ${WORKDIR}.
> > > And different images have different WORKDIR paths. So things should be
> > > safe.
> > >
> > > Which branch & version of poky or oe-core are you using?
> > >
> >
> > zeus
> >
> > > DEST_IMAGE_DIR is not defined in openembedded-core. Are you sure
> > > that's the right variable name?
> > >
> >
> > DEPLOY_DIR_IMAGE
> >
> > > Could you provide full bitbake output showing the exact error message
> > > when this collision happens?
> >
> > See traceback here:
> > https://ci.linaro.org/job/ledge-oe/357/DISTRO=rpb,MACHINE=ledge-stm32mp157c-dk2,label=docker-stretch-amd64/console
>
> I think I'm starting to understand now. Is this the wks file?
> https://github.com/Linaro/meta-ledge/blob/zeus/meta-ledge-bsp/wic/ledge-stm32mp157c-dk2-optee.wks.in

Got it. Nasty little bug there!

In the rawcopy source plugin, dst is set as follows:

    dst = os.path.join(cr_workdir, "%s.%s" % (source_params['file'],
part.lineno))

If source_params['file'] is an absolute path (as it is in the wks file
above), the cr_workdir prefix is not applied by os.path.join(). So
instead it writes to a ".1" file next to the original image - this is
outside the WORKDIR and at risk of collision.

The solution is to fix dst above, maybe use
os.path.basename(source_params['file']). Could you give that a try or
do you want me to propose a patch?

Thanks,
Paul


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