Currently working on refining the GrapheneOS Android 12 kernels so we can ship them tomorrow.
Stumbled upon a horrifying upstream bug and want to get it resolved instead of working around it. Looked a lot like a miscompilation caused by a compiler bug but it's weirder than that.
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It seems to be a linker bug introduced by the kernel LLVM being updated to 12.0.x for Android 12.
It doesn't impact 3rd generation Pixels despite them using the same LLVM toolchain because they still use ld.gold from an old version of binutils rather than ld.lld.