From: Steven Rostedt <rostedt@goodmis.org>
To: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Francis Deslauriers <francis.deslauriers@efficios.com>,
Peter Zijlstra <peterz@infradead.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 2/2] kprobe: fix: Add ftrace_ops_assist_func to kprobe blacklist
Date: Fri, 16 Mar 2018 23:01:54 -0400 [thread overview]
Message-ID: <20180316230154.2d34a98c@vmware.local.home> (raw)
In-Reply-To: <20180317102211.a648f26ae0d5a53d95c63022@kernel.org>
On Sat, 17 Mar 2018 10:22:11 +0900
Masami Hiramatsu <mhiramat@kernel.org> wrote:
> Or, we can check it by ftrace_location_range() as below patch.
Cute ;-)
>
> Note that as a side-effect, we can not trace functions in trace_kprobe.c
> anymore, and this means it is hard to me to make a testcase of kprobe events.
> It was the easiest (and maintainable) way to make test cases... sigh.
>
> -----
> tracing: kprobes: Prohibit probing on notrace function
>
> From: Masami Hiramatsu <mhiramat@kernel.org>
>
> Prohibit kprobe-events probing on notrace function.
> Since probing on the notrace function can cause recursive
> event call. In most case those are just skipped, but
> in some case it falls into infinit recursive call.
>
> Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
> ---
> kernel/trace/trace_kprobe.c | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index 5ce9b8cf7be3..7404b012e51a 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -487,6 +487,23 @@ disable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file)
> return ret;
> }
>
> +#ifdef CONFIG_KPROBES_ON_FTRACE
> +static bool within_notrace_func(struct trace_kprobe *tk)
> +{
> + unsigned long offset, size, addr;
> +
> + addr = kallsyms_lookup_name(trace_kprobe_symbol(tk));
> + addr += trace_kprobe_offset(tk);
> +
> + if (!kallsyms_lookup_size_offset(addr, &size, &offset))
> + return true; /* Out of range. */
> +
> + return !ftrace_location_range(addr - offset, addr - offset + size);
> +}
> +#else
> +#define within_notrace_func(tk) (false)
> +#endif
> +
> /* Internal register function - just handle k*probes and flags */
> static int __register_trace_kprobe(struct trace_kprobe *tk)
> {
> @@ -495,6 +512,12 @@ static int __register_trace_kprobe(struct trace_kprobe *tk)
> if (trace_probe_is_registered(&tk->tp))
> return -EINVAL;
>
> + if (within_notrace_func(tk)) {
> + pr_warn("Could not probe notrace function %s\n",
> + trace_kprobe_symbol(tk));
> + return -EINVAL;
> + }
This will prevent probing assembly code. Do we want to do that? Or is
kprobes already prohibited from doing so?
-- Steve
> +
> for (i = 0; i < tk->tp.nr_args; i++)
> traceprobe_update_arg(&tk->tp.args[i]);
>
>
next prev parent reply other threads:[~2018-03-17 3:01 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-14 14:58 [PATCH 0/2] kprobe: Fix: add symbols to kprobe blacklist Francis Deslauriers
2017-07-14 14:58 ` [PATCH 1/2] kprobe: fix: Add _ASM_NOKPROBE to x86 apic interrupt macro Francis Deslauriers
2017-07-14 14:58 ` [PATCH 2/2] kprobe: fix: Add ftrace_ops_assist_func to kprobe blacklist Francis Deslauriers
2017-07-14 18:29 ` Steven Rostedt
2018-03-16 15:18 ` Francis Deslauriers
2018-03-16 15:25 ` Steven Rostedt
2018-03-16 16:28 ` Mathieu Desnoyers
2018-03-16 16:41 ` Steven Rostedt
2018-03-16 16:48 ` Steven Rostedt
2018-03-16 17:53 ` Mathieu Desnoyers
2018-03-16 19:02 ` Steven Rostedt
2018-03-17 0:13 ` Masami Hiramatsu
2018-03-17 1:22 ` Masami Hiramatsu
2018-03-17 3:01 ` Steven Rostedt [this message]
2018-03-17 7:57 ` Masami Hiramatsu
2018-07-03 22:30 ` Steven Rostedt
2018-07-11 19:34 ` Francis Deslauriers
2018-07-11 19:56 ` Steven Rostedt
2018-07-12 0:40 ` Francis Deslauriers
2018-07-12 13:59 ` Masami Hiramatsu
2018-07-12 13:46 ` Masami Hiramatsu
2018-03-17 0:08 ` Masami Hiramatsu
2018-07-12 17:54 ` [PATCH 0/2] tracing: kprobes: Prohibit probing on notrace functions Francis Deslauriers
2018-07-12 17:54 ` [PATCH 1/2] " Francis Deslauriers
2018-07-12 21:49 ` Steven Rostedt
2018-07-13 2:53 ` Masami Hiramatsu
2018-07-13 12:18 ` Steven Rostedt
2018-07-26 0:41 ` Masami Hiramatsu
2018-07-26 1:13 ` Steven Rostedt
2018-07-12 17:54 ` [PATCH 2/2] selftest/ftrace: Move kprobe selftest function to separate compile unit Francis Deslauriers
2017-07-14 18:27 ` [PATCH 0/2] kprobe: Fix: add symbols to kprobe blacklist Steven Rostedt
2017-07-16 15:59 ` Masami Hiramatsu
2017-07-16 14:37 ` Masami Hiramatsu
2017-07-16 15:46 ` Masami Hiramatsu
2017-07-17 18:46 ` Francis Deslauriers
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180316230154.2d34a98c@vmware.local.home \
--to=rostedt@goodmis.org \
--cc=francis.deslauriers@efficios.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mathieu.desnoyers@efficios.com \
--cc=mhiramat@kernel.org \
--cc=peterz@infradead.org \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).