On Wed, Jun 5, 2019 at 11:42 AM Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote: > For the record, this is an example of why I think backporting those > clang enablement patches is a bad idea. There's always a risk involved with backports of any kind; more CI coverage can help us mitigate some of these risks in an automated fashion before we get user reports like this. I meet with the KernelCI folks weekly, so I'll double check on the coverage of the stable tree's branches. The 0day folks are also very responsive and I've spoken with them a few times, so I'll try to get to the bottom of why this wasn't reported by either of those. Also, these patches help keep Android, CrOS, and Google internal production kernels closer to their upstream sources. > We can't actually build those > kernels with clang, can we? So what is the point? </grumpy> Here's last night's build: https://travis-ci.com/ClangBuiltLinux/continuous-integration/builds/114388434 Also, Android and CrOS have shipped X million devices w/ 4.9 kernels built with Clang. I think this number will grow at least one order of magnitude imminently. > Alternatively, we can just revert this patch from 4.9 That would break at least the above devices next time Android and CrOS pulled from stable. > It would be helpful to get a relocation dump (objdump -r) of > arm64-stub.o to figure out which symbol needs a 'hidden' annotation to > prevent GCC from emitting it as a PIC reference requiring a GOT. Sounds like the best way forward, as well as having more info on which config/toolchain reliably reproduces the issue. -- Thanks, ~Nick Desaulniers
