Re: [PATCH bpf-next] bpf: trace jit code when enable BPF_JIT_ALWAYS_ON

[Alexei Starovoitov]

On Fri, Mar 26, 2021 at 5:40 AM Jianlin Lv <Jianlin.Lv@xxxxxxx> wrote:
>
> When CONFIG_BPF_JIT_ALWAYS_ON is enabled, the value of bpf_jit_enable in
> /proc/sys is limited to SYSCTL_ONE. This is not convenient for debugging.
> This patch modifies the value of extra2 (max) to 2 that support developers
> to emit traces on kernel log.
>
> Signed-off-by: Jianlin Lv <Jianlin.Lv@xxxxxxx>
> ---
>  net/core/sysctl_net_core.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
> index d84c8a1b280e..aa16883ac445 100644
> --- a/net/core/sysctl_net_core.c
> +++ b/net/core/sysctl_net_core.c
> @@ -386,7 +386,7 @@ static struct ctl_table net_core_table[] = {
>                 .proc_handler   = proc_dointvec_minmax_bpf_enable,
>  # ifdef CONFIG_BPF_JIT_ALWAYS_ON
>                 .extra1         = SYSCTL_ONE,
> -               .extra2         = SYSCTL_ONE,
> +               .extra2         = &two,

"bpftool prog dump jited" is much better way to examine JITed dumps.
I'd rather remove bpf_jit_enable=2 altogether.