linux-kernel - Re: [PATCH v9.1 07/11] tracing/probes: Add $$args meta argument for all function args

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:   Fri, 5 May 2023 17:48:56 -0400
From:   Steven Rostedt <rostedt@...dmis.org>
To:     "Masami Hiramatsu (Google)" <mhiramat@...nel.org>
Cc:     linux-trace-kernel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Florent Revest <revest@...omium.org>,
        Mark Rutland <mark.rutland@....com>,
        Will Deacon <will@...nel.org>,
        Mathieu Desnoyers <mathieu.desnoyers@...icios.com>,
        Martin KaFai Lau <martin.lau@...ux.dev>, bpf@...r.kernel.org
Subject: Re: [PATCH v9.1 07/11] tracing/probes: Add $$args meta argument for
 all function args

On Tue,  2 May 2023 11:18:21 +0900
"Masami Hiramatsu (Google)" <mhiramat@...nel.org> wrote:

> From: Masami Hiramatsu (Google) <mhiramat@...nel.org>
> 
> Add the '$$args' meta fetch argument for function-entry probe events. This

Hmm, couldn't we just use $args ? That would be different from $arg1,
$arg2, etc.

The $$ to me would be either the bash pid of current, or perhaps it would
be just to use a dollar sign. I don't see the precedence of $$args being a
"full expand".

-- Steve


> will be expanded to the all arguments of the function and the tracepoint
> using BTF function argument information.
> 
> e.g.
>  #  echo 'p vfs_read $$args' >> dynamic_events
>  #  echo 'f vfs_write $$args' >> dynamic_events
>  #  echo 't sched_overutilized_tp $$args' >> dynamic_events
>  # cat dynamic_events
> p:kprobes/p_vfs_read_0 vfs_read file=file buf=buf count=count pos=pos
> f:fprobes/vfs_write__entry vfs_write file=file buf=buf count=count pos=pos
> t:tracepoints/sched_overutilized_tp sched_overutilized_tp rd=rd overutilized=overutilized
> 
> Signed-off-by: Masami Hiramatsu (Google) <mhiramat@...nel.org>
> ---