Commit ccf74e79 authored Jan 08, 2025 by Sebastian Andrzej Siewior Committed by Petr Pavlu Mar 10, 2025

powerpc/ftrace: 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: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: linux-trace-kernel@vger.kernel.org
Cc: linuxppc-dev@lists.ozlabs.org
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Link: https://lore.kernel.org/r/20250108090457.512198-21-bigeasy@linutronix.de


Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>

parent 18d83c36

arch/powerpc/kernel/trace/ftrace.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -115,10 +115,8 @@ static unsigned long ftrace_lookup_module_stub(unsigned long ip, unsigned long a
		{
		struct module *mod = NULL;

		preempt_disable();
		scoped_guard(rcu)
		mod = __module_text_address(ip);
		preempt_enable();

		if (!mod)
		pr_err("No module loaded at addr=%lx\n", ip);

arch/powerpc/kernel/trace/ftrace_64_pg.c

+2 −4

Original line number	Diff line number	Diff line
		@@ -120,10 +120,8 @@ static struct module ftrace_lookup_module(struct dyn_ftrace rec)
		{
		struct module *mod;

		preempt_disable();
		scoped_guard(rcu)
		mod = __module_text_address(rec->ip);
		preempt_enable();

		if (!mod)
		pr_err("No module loaded at addr=%lx\n", rec->ip);