[yocto] do_make_scripts race condition with externalsrc

[Mikhail Zakharov]

Hello,

We are having problems with using externalsrc.bbclass for building
kernel modules (module.bbclass)

When building multiple kernel modules from clean workspace in parallel,
if one of the modules inherits externalsrc, the build will fail with the
following error:

OSError: [Errno 20] Not a directory:
'/home/user/poky/tmp/kernel-scripts.lock/home'
ERROR: Task 3
(/home/user/poky/meta-custom/recipes-kernel/externalsrc-module/externalsrc-module.bb,
do_make_scripts)

full error log:
http://pastebin.com/aP5GMcsw

contents of externalsrc-module.bb:
http://pastebin.com/QXY2r7dx

re-running bitbake after the failure allows the build to complete
successfully.

Any help with solutions/workarounds for this would be greatly appreciated.

Kind regards,
Mikhail