From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Date: Wed, 8 Jan 2025 10:04:52 +0100 Subject: [PATCH 23/28] 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> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org> Link: https://lore.kernel.org/r/20250108090457.512198-24-bigeasy@linutronix.de Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- kernel/jump_label.c | 18 +++++++++--------- 1 file changed, 9 insertions(+), 9 deletions(-) @ kernel/jump_label.c:749 @ static int jump_label_add_module(struct kfree(jlm); return -ENOMEM; } - preempt_disable(); - jlm2->mod = __module_address((unsigned long)key); - preempt_enable(); + scoped_guard(rcu) + jlm2->mod = __module_address((unsigned long)key); + jlm2->entries = static_key_entries(key); jlm2->next = NULL; static_key_set_mod(key, jlm2); @ kernel/jump_label.c:909 @ static void jump_label_update(struct sta return; } - preempt_disable(); - mod = __module_address((unsigned long)key); - if (mod) { - stop = mod->jump_entries + mod->num_jump_entries; - init = mod->state == MODULE_STATE_COMING; + 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 */