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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> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240411102158.1272267-1-elver@google.com> X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 087BC40006 X-Stat-Signature: umqzdwtos9aijgryqfxzb9fgzftf1mwk X-HE-Tag: 1712848507-157813 X-HE-Meta: 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 JBiS0zqE wVWYQQhQGedeUWIedVcRRLy2SpYevJgptZy+euqn9ytLKV4SnGJvz2R4E0LWkUfpYfJFEKWJNEqeAIBUnbPi6ofwZtlxg8iGtixxEEhrFXFvSslCOggfx4mI1BhFKy9pjWOGF X-Bogosity: Ham, tests=bogofilter, spamicity=0.000475, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: 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