[llvm] [BOLT] Add CustomOffset flag for optimizing kernel (PR #98153)

[via llvm-commits]

lifengxiang1025 wrote:

> Did you check that if you disable KASLR, the problem will go away? Also, disabling KASLR might be a security vulnerability so it's unclear whether we want to recommend it.

Yes. When we disable KASLR, symbol's address in `/proc/kallsyms` is same as address in `vmlinux`. If we enable KASLR, there is one fixed offset between `/proc/kallsyms` and `vmlinux`. The fixed offset is changed after rebooting.
Again, we are not expert in kernel. This is what we observed.

https://github.com/llvm/llvm-project/pull/98153