build failure with certain cowbuilder

I've got a build failure with freewnn via cowbuilder. However, same source can be built with pbuilder. And strangely, cowbuilder  in another host can build it.

  • host + pbuilder = fine
  • host + cowbuilder = fail
  • host(chroot) + cowbuilder = fine
  • host(old kernel) + cowbuilder = fine
  • laptop + pbuilder = fine
  • laptop + cowbuilder = fine
  • virtualbox + cowbuilder = fine
... it's strange. What is the root cause of this?

Comments