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[188.141.5.72]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-4a1c10fe9d3sm98463075e9.13.2026.10.15.22.38.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 15 Oct 2026 22:38:38 -0700 (PDT) From: David Carlier To: rostedt@goodmis.org, mhiramat@kernel.org Cc: mathieu.desnoyers@efficios.com, linux-trace-kernel@vger.kernel.org, linux-kernel@vger.kernel.org, David Carlier , stable@vger.kernel.org Subject: [PATCH] tracing: Hold trace_types_lock when updating modules in persistent instances Date: Fri, 16 Oct 2026 06:38:35 +0100 Message-ID: <20261016053835.204353-1-devnexen@gmail.com> X-Mailer: git-send-email 2.55.0 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit trace_module_record() walks ftrace_trace_arrays from the module notifier without trace_types_lock. A concurrent rmdir of an instance removes it from the list and frees it under that lock, so a module load or unload can walk into a freed trace_array. The notifier also reads and updates tr->scratch and tr->module_delta while update_last_data() may be resetting them. Fixes: 5f3719f697c3 ("tracing: Update modules to persistent instances when loaded") Cc: stable@vger.kernel.org --- kernel/trace/trace.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index e4a490d3d08c..d3ffbed9c44b 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -9247,6 +9247,8 @@ static void trace_module_record(struct module *mod, bool add) struct trace_array *tr; unsigned long flags; + guard(mutex)(&trace_types_lock); + list_for_each_entry(tr, &ftrace_trace_arrays, list) { flags = tr->flags & (TRACE_ARRAY_FL_BOOT | TRACE_ARRAY_FL_LAST_BOOT); /* Update any persistent trace array that has already been started */ -- 2.55.0