From: Steven Rostedt <rostedt@goodmis.org>
To: Anubhav Shelat <ashelat@redhat.com>
Cc: mpetlan@redhat.com, Masami Hiramatsu <mhiramat@kernel.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Namhyung Kim <namhyung@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
James Clark <james.clark@linaro.org>,
Thomas Falcon <thomas.falcon@intel.com>,
linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org,
linux-perf-users@vger.kernel.org
Subject: Re: [PATCH v4 3/3] tracefs: make root directory world-traversable
Date: Fri, 15 May 2026 19:16:30 -0400 [thread overview]
Message-ID: <20260515191630.2276b241@fedora> (raw)
In-Reply-To: <20260515194010.93725-5-ashelat@redhat.com>
On Fri, 15 May 2026 15:40:07 -0400
Anubhav Shelat <ashelat@redhat.com> wrote:
> Change the default tracefs mount mode from 0700 to 0755. This allows
> unprivileged users to access the eventfs directories underneath which
> already use 0755.
>
> Tracing data files use mode 0440 and 0640 so they are not exposed by
> this change. Only the format and id files, which have been marked as
> work-readable, become accessible.
>
> Directory listings of kprobes and uprobes, which contain functions or
> binaries, become visible to unprivileged users but do not contain kernel
> addresses. Admins using probes can restore the previous behavior with
> chmod or mount -o mode=700.
>
I've been thinking about this and I believe a better approach is to
make a eventfs that is mounted at:
/sys/kernel/events
and be the same directory structure as /sys/kernel/tracing/events but
only contain read only files like "id" and "format". This directory
would be mounted as 555 and readable by all.
-- Steve
prev parent reply other threads:[~2026-05-15 23:16 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-15 19:40 [PATCH v4 0/3] Enable perf tracing for unprivileged users Anubhav Shelat
2026-05-15 19:40 ` [PATCH v4 1/3] perf evsel: don't set PERF_SAMPLE_IP for unprivileged tracepoints Anubhav Shelat
2026-05-15 20:10 ` sashiko-bot
2026-05-15 19:40 ` [PATCH v4 2/3] perf: enable unprivileged syscall tracing with perf trace Anubhav Shelat
2026-05-15 19:40 ` [PATCH v4 3/3] tracefs: make root directory world-traversable Anubhav Shelat
2026-05-15 23:16 ` Steven Rostedt [this message]
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