Re: [PATCH v2 3/4] tracing/kprobes: Don't pass addr=ip to perf_trace_buf_submit()

[Steven Rostedt <rostedt@goodmis.org>]

On Thu, 2013-06-20 at 19:38 +0200, Oleg Nesterov wrote:
> kprobe_perf_func() and kretprobe_perf_func() pass addr=ip to
> perf_trace_buf_submit() for no reason.
> 
> This sets perf_sample_data->addr for PERF_SAMPLE_ADDR, we already
> have perf_sample_data->ip initialized if PERF_SAMPLE_IP.

This change log is confusing. I have no idea what this is trying to fix.
Can you explain what is the issue here and what this change fixes.

Thanks,

-- Steve

> 
> Signed-off-by: Oleg Nesterov <oleg@redhat.com>
> ---
>  kernel/trace/trace_kprobe.c |    6 ++----
>  1 files changed, 2 insertions(+), 4 deletions(-)
> 
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 3432652..141c682 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -1163,8 +1163,7 @@ kprobe_perf_func(struct trace_probe *tp, struct pt_regs *regs)
>  	entry->ip = (unsigned long)tp->rp.kp.addr;
>  	memset(&entry[1], 0, dsize);
>  	store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
> -	perf_trace_buf_submit(entry, size, rctx,
> -					entry->ip, 1, regs, head, NULL);
> +	perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
>  }
>  
>  /* Kretprobe profile handler */
> @@ -1197,8 +1196,7 @@ kretprobe_perf_func(struct trace_probe *tp, struct kretprobe_instance *ri,
>  	entry->func = (unsigned long)tp->rp.kp.addr;
>  	entry->ret_ip = (unsigned long)ri->ret_addr;
>  	store_trace_args(sizeof(*entry), tp, regs, (u8 *)&entry[1], dsize);
> -	perf_trace_buf_submit(entry, size, rctx,
> -					entry->ret_ip, 1, regs, head, NULL);
> +	perf_trace_buf_submit(entry, size, rctx, 0, 1, regs, head, NULL);
>  }
>  #endif	/* CONFIG_PERF_EVENTS */
>