On Wed, Apr 04, 2018 at 04:53:52PM +0000, Nick Desaulniers wrote: > (re-sending as plain text) > > On Wed, Apr 4, 2018 at 2:38 AM Greg KH <gre...@linuxfoundation.org> wrote: > > There are known-bugs with building a kernel with clang right now (I > > pointed one out a few days ago about NULL checks being deleted from the > > clang output for no good reason, which really is scary for obvious > > reasons). > > Is this the thread you are referring to? > https://lkml.org/lkml/2018/3/27/1286 > > It's definitely something curious that I'll need to sit down and > investigate more. If there are other known instances, it would be good to > let me know.
As Matthias mentioned elsewhere, it sounds like they're planning to implement -fno-delete-null-pointer-checks, which would presumably fix the above issue. Aside from the above-mentioned debugfs NULL checks, there was also another (seemingly valid) objtool warning: arch/x86/mm/pti.o: warning: objtool: pti_init() falls through to next function pti_user_pagetable_walk_pmd() I don't know if that one was also caused by removed NULL checks, but it's worth investigating. More details (and the .o file) here: https://lkml.kernel.org/r/20180319232255.gf37...@google.com -- Josh