On Thu, Mar 04, 2021 at 09:27:28PM +0900, Masahiro Yamada wrote: > I agree with rebuilding GCC plugins when the compiler is upgraded > for *in-tree* building. > Linus had reported it a couple of months before, > and I just submitted a very easy fix. Hm? So does that mean that a GCC version change won't trigger a tree-wide rebuild? So you're asserting that a GCC mismatch is ok for in-tree code, but not for external modules??? That seems backwards. For in-tree, why not just rebuild the entire tree? Some kernel features are dependent on compiler version or capability, so not rebuilding the tree could introduce silent breakage. For external modules, a tree-wide rebuild isn't an option so the risk is assumed by the user. I posted a patch earlier [1] which prints a warning if the compiler major/minor version changes with an external module build. [1] https://lkml.kernel.org/r/20210201211322.t2rxmvnrystc2ky7@treble > Rebuilding plugins for external modules is not easy; > plugins are placed in the read-only directory, > /usr/src/linux-headers-$(uname -r)/scripts/gcc-plugins/. > > The external modules must not (cannot) update in-tree > build artifacts. "Rebuild" means creating copies in a different > writable directory. > Doing that requires a lot of design changes. Ok. So it sounds like the best/easiest option is the original patch in this thread: when building an external module with a GCC mismatch, just disable the GCC plugin, with a warning (or an error for randstruct). -- Josh
