On Thu, Aug 1, 2019 at 9:39 AM Sedat Dilek <sedat.dilek@xxxxxxxxx> wrote:
>
> Hi,
>
> just want to let you know that I did a git bisect with Linux v5.3-rc2
> (where the problem also exists) and the result (details see [1]):
>
> e55a73251da335873a6e87d68fb17e5aabb8978e is the first bad commit
> commit e55a73251da335873a6e87d68fb17e5aabb8978e
> Author: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> Date: Thu Jun 27 20:50:47 2019 -0500
>
> bpf: Fix ORC unwinding in non-JIT BPF code
>
> Objtool previously ignored ___bpf_prog_run() because it didn't understand
> the jump table. This resulted in the ORC unwinder not being able to unwind
> through non-JIT BPF code.
>
> Now that objtool knows how to read jump tables, remove the whitelist and
> annotate the jump table so objtool can recognize it.
>
> Also add an additional "const" to the jump table definition to clarify that
> the text pointers are constant. Otherwise GCC sets the section writable
> flag and the assembler spits out warnings.
>
> Fixes: d15d356887e7 ("perf/x86: Make perf callchains work without
> CONFIG_FRAME_POINTER")
> Reported-by: Song Liu <songliubraving@xxxxxx>
> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Acked-by: Alexei Starovoitov <ast@xxxxxxxxxx>
> Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Cc: Kairui Song <kasong@xxxxxxxxxx>
> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
> Cc: Borislav Petkov <bp@xxxxxxxxx>
> Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> Link: https://lkml.kernel.org/r/881939122b88f32be4c374d248c09d7527a87e35.1561685471.git.jpoimboe@xxxxxxxxxx
> Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
>
> :040000 040000 4735e9d14fa416c1c361ec3923440a3d586a627d
> 31de80b85c7b0292e47a719ecb6b1a451de2f8ef M kernel
>
> Maybe you want to look at this, too.
>
> The object files are attached in [2].
>
> Thanks,
> - Sedat -
>
> [0] https://github.com/ClangBuiltLinux/linux/issues/619
> [1] https://github.com/ClangBuiltLinux/linux/issues/619#issuecomment-517152467
> [2] https://github.com/ClangBuiltLinux/linux/issues/619#issuecomment-517159635
After reverting above commit I can boot into Linux v5.3-rc2 built with
clang-9.0.0-rc1 and lld with no issues.
- Sedat -
