Subject: [PATCH 20/28] powerpc/ftrace: Use RCU in all users of __module_text_address().
From: Sebastian Andrzej Siewior <[email-masked]>
Date: Wed, 8 Jan 2025 10:04:49 +0100

__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: Christophe Leroy <[email-masked]>
Cc: Madhavan Srinivasan <[email-masked]>
Cc: Mark Rutland <[email-masked]>
Cc: Masami Hiramatsu <[email-masked]>
Cc: Michael Ellerman <[email-masked]>
Cc: Naveen N Rao <[email-masked]>
Cc: Nicholas Piggin <[email-masked]>
Cc: Steven Rostedt <[email-masked]>
Cc: [email-masked]
Cc: [email-masked]
Acked-by: Peter Zijlstra (Intel) <[email-masked]>
Link: https://lore.kernel.org/r/[email-masked]
Signed-off-by: Sebastian Andrzej Siewior <[email-masked]>
---
 arch/powerpc/kernel/trace/ftrace.c       |    6 ++----
 arch/powerpc/kernel/trace/ftrace_64_pg.c |    6 ++----
 2 files changed, 4 insertions(+), 8 deletions(-)

--- a/arch/powerpc/kernel/trace/ftrace.c
+++ b/arch/powerpc/kernel/trace/ftrace.c
@@ -115,10 +115,8 @@ static unsigned long ftrace_lookup_modul
 {
 	struct module *mod = NULL;
 
-	preempt_disable();
-	mod = __module_text_address(ip);
-	preempt_enable();
-
+	scoped_guard(rcu)
+		mod = __module_text_address(ip);
 	if (!mod)
 		pr_err("No module loaded at addr=%lx\n", ip);
 
--- a/arch/powerpc/kernel/trace/ftrace_64_pg.c
+++ b/arch/powerpc/kernel/trace/ftrace_64_pg.c
@@ -120,10 +120,8 @@ static struct module *ftrace_lookup_modu
 {
 	struct module *mod;
 
-	preempt_disable();
-	mod = __module_text_address(rec->ip);
-	preempt_enable();
-
+	scoped_guard(rcu)
+		mod = __module_text_address(rec->ip);
 	if (!mod)
 		pr_err("No module loaded at addr=%lx\n", rec->ip);