From: Steven Rostedt <rostedt@goodmis.org>
To: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>, Jiri Olsa <jolsa@kernel.org>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org,
bpf@vger.kernel.org
Subject: Re: [PATCH bpf v2 1/2] fprobe: samples: Add use_trace option and show hit/missed counter
Date: Fri, 17 Jun 2022 12:06:51 -0400 [thread overview]
Message-ID: <20220617120651.1e525a02@gandalf.local.home> (raw)
In-Reply-To: <165461826247.280167.11939123218334322352.stgit@devnote2>
On Wed, 8 Jun 2022 01:11:02 +0900
"Masami Hiramatsu (Google)" <mhiramat@kernel.org> wrote:
>
> static void sample_entry_handler(struct fprobe *fp, unsigned long ip, struct pt_regs *regs)
> {
> - pr_info("Enter <%pS> ip = 0x%p\n", (void *)ip, (void *)ip);
> + if (use_trace)
> + trace_printk("Enter <%pS> ip = 0x%p\n", (void *)ip, (void *)ip);
Could we add a comment stating something like "this is just an example, no
kernel code should call trace_printk() except when actively debugging".
-- Steve
> + else
> + pr_info("Enter <%pS> ip = 0x%p\n", (void *)ip, (void *)ip);
> + nhit++;
> if (stackdump)
> show_backtrace();
> }
> @@ -49,8 +56,13 @@ static void sample_exit_handler(struct fprobe *fp, unsigned long ip, struct pt_r
> {
> unsigned long rip = instruction_pointer(regs);
>
> - pr_info("Return from <%pS> ip = 0x%p to rip = 0x%p (%pS)\n",
> - (void *)ip, (void *)ip, (void *)rip, (void *)rip);
> + if (use_trace)
> + trace_printk("Return from <%pS> ip = 0x%p to rip = 0x%p (%pS)\n",
> + (void *)ip, (void *)ip, (void *)rip, (void *)rip);
> + else
> + pr_info("Return from <%pS> ip = 0x%p to rip = 0x%p (%pS)\n",
> + (void *)ip, (void *)ip, (void *)rip, (void *)rip);
> + nhit++;
> if (stackdump)
> show_backtrace();
next prev parent reply other threads:[~2022-06-17 16:06 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-07 16:10 [PATCH bpf v2 0/2] rethook: Reject getting a rethook if RCU is not watching Masami Hiramatsu (Google)
2022-06-07 16:11 ` [PATCH bpf v2 1/2] fprobe: samples: Add use_trace option and show hit/missed counter Masami Hiramatsu (Google)
2022-06-17 16:06 ` Steven Rostedt [this message]
2022-06-22 1:41 ` Masami Hiramatsu
2022-06-07 16:11 ` [PATCH bpf v2 2/2] rethook: Reject getting a rethook if RCU is not watching Masami Hiramatsu (Google)
2022-06-17 16:19 ` Steven Rostedt
2022-06-17 11:27 ` [PATCH bpf v2 0/2] " Jiri Olsa
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