From: Steven Rostedt <rostedt@goodmis.org>
To: Jianlin Lv <Jianlin.Lv@arm.com>
Cc: mingo@redhat.com, linux-kernel@vger.kernel.org,
Masami Hiramatsu <mhiramat@kernel.org>
Subject: Re: [PATCH v2] tracing: precise log info for kretprobe addr err
Date: Wed, 20 Jan 2021 11:20:04 -0500 [thread overview]
Message-ID: <20210120112004.4b9ff1df@gandalf.local.home> (raw)
In-Reply-To: <20210120155644.64721-1-Jianlin.Lv@arm.com>
You forgot to include Masami on Cc again. Masami maintains kprobes. Please
include him on any updates, as he needs to review them, and give his
acknowledgment before acceptance.
I need to update MAINTAINERS files to include trace_kprobe under KPROBES.
And I also don't see any UPROBES section there. That needs to be done as
well.
On Wed, 20 Jan 2021 23:56:44 +0800
Jianlin Lv <Jianlin.Lv@arm.com> wrote:
> When trying to create kretprobe with the wrong function symbol in tracefs;
> The error is triggered in the register_trace_kprobe() and recorded as
> FAIL_REG_PROBE issue,
>
> Example:
> $ cd /sys/kernel/debug/tracing
> $ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events
> bash: echo: write error: Invalid argument
> $ cat error_log
> [142797.347877] trace_kprobe: error: Failed to register probe event
> Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0
> ^
>
> This error can be detected in the parameter parsing stage, the effect of
> applying this patch is as follows:
>
> $ echo 'r:myprobe ERROR_SYMBOL_XXX ret=%x0' >> kprobe_events
> bash: echo: write error: Invalid argument
> $ cat error_log
> [415.89]trace_kprobe: error: Retprobe address must be an function entry
> Command: r:myprobe ERROR_SYMBOL_XXX ret=%x0
> ^
>
> Signed-off-by: Jianlin Lv <Jianlin.Lv@arm.com>
>
> v2:add !strchr(symbol, ':') to check really bad symbol or not.
Also, the "changes since" section should be below the "---" so that they
don't get pulled into the commit.
Thanks!
-- Steve
> ---
> kernel/trace/trace_kprobe.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
> index e6fba1798771..bce63d5ecaec 100644
> --- a/kernel/trace/trace_kprobe.c
> +++ b/kernel/trace/trace_kprobe.c
> @@ -830,7 +830,7 @@ static int trace_kprobe_create(int argc, const char *argv[])
> flags |= TPARG_FL_RETURN;
> if (kprobe_on_func_entry(NULL, symbol, offset))
> flags |= TPARG_FL_FENTRY;
> - if (offset && is_return && !(flags & TPARG_FL_FENTRY)) {
> + if (!strchr(symbol, ':') && is_return && !(flags & TPARG_FL_FENTRY)) {
> trace_probe_log_err(0, BAD_RETPROBE);
> goto parse_error;
> }
next prev parent reply other threads:[~2021-01-20 16:23 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-20 15:56 [PATCH v2] tracing: precise log info for kretprobe addr err Jianlin Lv
2021-01-20 16:20 ` Steven Rostedt [this message]
2021-01-21 2:28 ` Masami Hiramatsu
2021-01-23 14:21 ` Jianlin Lv
2021-01-24 8:52 ` Masami Hiramatsu
2021-01-25 3:14 ` Jianlin Lv
2021-01-25 14:42 ` Steven Rostedt
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