[PATCH v3 19/28] LoongArch: ftrace: Use RCU in all users of __module_text_address().
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: 2025-01-08 09:05:23
Also in:
linux-modules, lkml, loongarch
Subsystem:
function hooks (ftrace), loongarch, the rest · Maintainers:
Steven Rostedt, Masami Hiramatsu, Huacai Chen, Linus Torvalds
__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: Huacai Chen <chenhuacai@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: WANG Xuerui <kernel@xen0n.name> Cc: linux-trace-kernel@vger.kernel.org Cc: loongarch@lists.linux.dev Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- arch/loongarch/kernel/ftrace_dyn.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/arch/loongarch/kernel/ftrace_dyn.c b/arch/loongarch/kernel/ftrace_dyn.c
index 18056229e22e4..5b7b8ac13e350 100644
--- a/arch/loongarch/kernel/ftrace_dyn.c
+++ b/arch/loongarch/kernel/ftrace_dyn.c@@ -85,14 +85,13 @@ static bool ftrace_find_callable_addr(struct dyn_ftrace *rec, struct module *mod * 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(); - mod = __module_text_address(pc); - preempt_enable(); + scoped_guard(rcu) + mod = __module_text_address(pc); } if (WARN_ON(!mod))
--
2.47.1