[OE-core] Cannot build any external kernel modules in krogoth

[Ian Geiser]

 ---- On Tue, 30 Aug 2016 10:13:52 -0400 Ian Geiser <geiseri at geekcentral.pub> wrote ---- 
 > Greetings,  I have an issue where I cannot seem to build any external kernel module recipes.  The one in particular is iscsitarget, but it seems none of them build now. 
 >  
 > It seems that what is happening is that the "work-shared/*/kernel-build-artifacts" is getting erased right before the module recipe tries to use them.  Has anyone seen this before? 
 >  
 > As a key point, I am also using my own kernel recipe that only uses the kernel.bbclass, not the kernel-yocto.bbclass.  Is there magic I am missing that will not allow me to build modules unless I am using the yocto kernels? 
 >  
 
Looking at this further it looks like this is a normal issue with all kernels.  There is a race condition that will cause the kernel to rebuild everytime you build a module.  During this process the build artifacts are always cleared out and sometimes it wont actually populate the shared workdir.  I tested with most kernels and found all modules suffer this issue.  Am I the only one seeing this?