Re: [PATCH 2/2] arm64: bpf: add extra pass to handle faulty codegen

On Wed, Jan 13, 2016 at 11:33:22PM -0800, Zi Shen Lim wrote:

Code generation functions in arch/arm64/kernel/insn.c previously
BUG_ON invalid parameters. Following change of that behavior, now we
need to handle the error case where AARCH64_BREAK_FAULT is returned.

Instead of error-handling on every emit() in JIT, we add a new
validation pass at the end of JIT compilation. There's no point in
running JITed code at run-time only to trap due to AARCH64_BREAK_FAULT.
Instead, we drop this failed JIT compilation and allow the system to
gracefully fallback on the BPF interpreter.

Signed-off-by: Zi Shen Lim <redacted>
Suggested-by: Alexei Starovoitov <ast@kernel.org>

Looks good to me.
Acked-by: Alexei Starovoitov <ast@kernel.org>
technically it's a bug fix, though the shift problem is already mitigated.
Will, any comments?