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Date: Tue, 9 Apr 2024 10:33:27 -0400
From: Steven Rostedt <rostedt@goodmis.org>
To: Marco Elver <elver@google.com>
Cc: Eric Biederman <ebiederm@xmission.com>, Kees Cook
 <keescook@chromium.org>, Alexander Viro <viro@zeniv.linux.org.uk>,
 Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>, Masami
 Hiramatsu <mhiramat@kernel.org>, Mathieu Desnoyers
 <mathieu.desnoyers@efficios.com>, linux-mm@kvack.org,
 linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
 linux-trace-kernel@vger.kernel.org, Dmitry Vyukov <dvyukov@google.com>
Subject: Re: [PATCH] tracing: Add new_exec tracepoint
Message-ID: <20240409103327.7a9012fa@gandalf.local.home>
In-Reply-To: <20240408090205.3714934-1-elver@google.com>
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On Mon,  8 Apr 2024 11:01:54 +0200
Marco Elver <elver@google.com> wrote:

> Add "new_exec" tracepoint, which is run right after the point of no
> return but before the current task assumes its new exec identity.
> 
> Unlike the tracepoint "sched_process_exec", the "new_exec" tracepoint
> runs before flushing the old exec, i.e. while the task still has the
> original state (such as original MM), but when the new exec either
> succeeds or crashes (but never returns to the original exec).
> 
> Being able to trace this event can be helpful in a number of use cases:
> 
>   * allowing tracing eBPF programs access to the original MM on exec,
>     before current->mm is replaced;
>   * counting exec in the original task (via perf event);
>   * profiling flush time ("new_exec" to "sched_process_exec").
> 
> Example of tracing output ("new_exec" and "sched_process_exec"):

How common is this? And can't you just do the same with adding a kprobe?

-- Steve