Commit 4038131f authored by Sebastian Andrzej Siewior's avatar Sebastian Andrzej Siewior Committed by Petr Pavlu
Browse files

jump_label: Use RCU in all users of __module_address(). 



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

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

Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Jason Baron <jbaron@akamai.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250108090457.512198-24-bigeasy@linutronix.de


Signed-off-by: default avatarPetr Pavlu <petr.pavlu@suse.com>
parent 14daa3bc

kernel/jump_label.c

+9 −9
Original line number Diff line number Diff line
@@ -746,9 +746,9 @@ static int jump_label_add_module(struct module *mod) 
				kfree(jlm);

				return -ENOMEM;

			}

			preempt_disable();

			scoped_guard(rcu)

				jlm2->mod = __module_address((unsigned long)key);

			preempt_enable();



			jlm2->entries = static_key_entries(key);

			jlm2->next = NULL;

			static_key_set_mod(key, jlm2);
@@ -906,13 +906,13 @@ static void jump_label_update(struct static_key *key) 
		return;

	}



	preempt_disable();

	scoped_guard(rcu) {

		mod = __module_address((unsigned long)key);

		if (mod) {

			stop = mod->jump_entries + mod->num_jump_entries;

			init = mod->state == MODULE_STATE_COMING;

		}

	preempt_enable();

	}

#endif

	entry = static_key_entries(key);

	/* if there are no users, entry can be NULL */