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Thu, 11 Apr 2024 08:15:06 -0700 (PDT) Received: from www.outflux.net ([198.0.35.241]) by smtp.gmail.com with ESMTPSA id e6-20020a17090ac20600b0029bf9969afbsm2963349pjt.53.2024.04.11.08.15.06 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 11 Apr 2024 08:15:06 -0700 (PDT) Date: Thu, 11 Apr 2024 08:15:05 -0700 From: Kees Cook To: Marco Elver Cc: Steven Rostedt , Alexander Viro , Christian Brauner , Jan Kara , Eric Biederman , Masami Hiramatsu , Mathieu Desnoyers , Azeem Shaikh , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, Dmitry Vyukov Subject: Re: [PATCH v2] tracing: Add sched_prepare_exec tracepoint Message-ID: <202404110814.B219872F76@keescook> References: <20240411102158.1272267-1-elver@google.com> Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240411102158.1272267-1-elver@google.com> On Thu, Apr 11, 2024 at 12:20:57PM +0200, Marco Elver wrote: > Add "sched_prepare_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 "sched_prepare_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 ("sched_prepare_exec" to "sched_process_exec"). > > Example of tracing output: > > $ cat /sys/kernel/debug/tracing/trace_pipe > <...>-379 [003] ..... 179.626921: sched_prepare_exec: interp=/usr/bin/sshd filename=/usr/bin/sshd pid=379 comm=sshd > <...>-381 [002] ..... 180.048580: sched_prepare_exec: interp=/bin/bash filename=/bin/bash pid=381 comm=sshd > <...>-385 [001] ..... 180.068277: sched_prepare_exec: interp=/usr/bin/tty filename=/usr/bin/tty pid=385 comm=bash > <...>-389 [006] ..... 192.020147: sched_prepare_exec: interp=/usr/bin/dmesg filename=/usr/bin/dmesg pid=389 comm=bash > > Signed-off-by: Marco Elver This looks good to me. If tracing wants to take it: Acked-by: Kees Cook If not, I can take it in my tree if I get a tracing Ack. :) -Kees -- Kees Cook