Commit 17a9992d authored Jan 08, 2025 by Sebastian Andrzej Siewior Committed by Petr Pavlu Mar 10, 2025

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>

parent 59aa1414

arch/arm64/kernel/ftrace.c

+3 −4

Original line number	Diff line number	Diff line
		@@ -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))