module: Use RCU in __is_module_percpu_address().

The modules list can be accessed under RCU assumption.

Use RCU protection instead preempt_disable().

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250108090457.512198-12-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>

diff --git a/kernel/module/main.c b/kernel/module/main.c
index af7ca713eff0a75ba3a0ee2c48be86c0a6314651..5d6f44c09bec250500d9a7b068a5d721196f2f93 100644 (file)
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -450,8 +450,7 @@ bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
        struct module *mod;
        unsigned int cpu;
 
-       preempt_disable();
-
+       guard(rcu)();
        list_for_each_entry_rcu(mod, &modules, list) {
                if (mod->state == MODULE_STATE_UNFORMED)
                        continue;
@@ -468,13 +467,10 @@ bool __is_module_percpu_address(unsigned long addr, unsigned long *can_addr)
                                                per_cpu_ptr(mod->percpu,
                                                            get_boot_cpu_id());
                                }
-                               preempt_enable();
                                return true;
                        }
                }
        }
-
-       preempt_enable();
        return false;
 }