arm64: module: Use RCU in all users of __module_text_address().

__module_text_address() can be invoked within a RCU section, there is no
requirement to have preemption disabled.

Replace the preempt_disable() section around __module_text_address()
with RCU.

Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Will Deacon <will@kernel.org>
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-trace-kernel@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250108090457.512198-18-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>

diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c
index d7c0d023dfe5e686b75f926198c29097d078e330..5a890714ee2e987b6712b2aff852c1994940d6d6 100644 (file)
--- a/arch/arm64/kernel/ftrace.c
+++ b/arch/arm64/kernel/ftrace.c
@@ -320,14 +320,13 @@ static bool ftrace_find_callable_addr(struct dyn_ftrace *rec,
         * dealing with an out-of-range condition, we can assume it
         * is due to a module being loaded far away from the kernel.
         *
-        * NOTE: __module_text_address() must be called with preemption
-        * disabled, but we can rely on ftrace_lock to ensure that 'mod'
+        * NOTE: __module_text_address() must be called within a RCU read
+        * section, but we can rely on ftrace_lock to ensure that 'mod'
         * retains its validity throughout the remainder of this code.
         */
        if (!mod) {
-               preempt_disable();
+               guard(rcu)();
                mod = __module_text_address(pc);
-               preempt_enable();
        }
 
        if (WARN_ON(!mod))