Re: [PATCH 0/2] ftrace: make sure preemption disabled on recursion testing

[Palmer Dabbelt]

On Mon, 11 Oct 2021 22:39:16 PDT (-0700), yun.wang@xxxxxxxxxxxxxxxxx wrote:
> The testing show that perf_ftrace_function_call() are using
> smp_processor_id() with preemption enabled, all the checking
> on CPU could be wrong after preemption, PATCH 1/2 will fix
> that.
>
> Besides, as Peter point out, the testing of recursion within
> the section between ftrace_test_recursion_trylock()/_unlock()
> pair also need the preemption disabled as the documentation
> explained, PATCH 2/2 will make sure on that.
>
> Michael Wang (2):
>   ftrace: disable preemption on the testing of recursion
>   ftrace: prevent preemption in perf_ftrace_function_call()
>
>  arch/csky/kernel/probes/ftrace.c     |  2 --
>  arch/parisc/kernel/ftrace.c          |  2 --
>  arch/powerpc/kernel/kprobes-ftrace.c |  2 --
>  arch/riscv/kernel/probes/ftrace.c    |  2 --
>  arch/x86/kernel/kprobes/ftrace.c     |  2 --
>  include/linux/trace_recursion.h      | 10 +++++++++-
>  kernel/livepatch/patch.c             |  6 ------
>  kernel/trace/trace_event_perf.c      | 17 +++++++++++++----
>  kernel/trace/trace_functions.c       |  5 -----
>  9 files changed, 22 insertions(+), 26 deletions(-)

Acked-by: Palmer Dabbelt <palmerdabbelt@xxxxxxxxxx> # RISC-V