Subject: [PATCH 07/28] module: Use RCU in __find_kallsyms_symbol_value().
From: Sebastian Andrzej Siewior <[email-masked]>
Date: Wed, 8 Jan 2025 10:04:36 +0100

module::kallsyms can be accessed under RCU assumption.

Use rcu_dereference() to access module::kallsyms.
Update callers.

Acked-by: Peter Zijlstra (Intel) <[email-masked]>
Link: https://lore.kernel.org/r/[email-masked]
Signed-off-by: Sebastian Andrzej Siewior <[email-masked]>
---
 kernel/module/kallsyms.c |   17 ++++-------------
 1 file changed, 4 insertions(+), 13 deletions(-)

--- a/kernel/module/kallsyms.c
+++ b/kernel/module/kallsyms.c
@@ -407,7 +407,7 @@ int module_get_kallsym(unsigned int symn
 static unsigned long __find_kallsyms_symbol_value(struct module *mod, const char *name)
 {
 	unsigned int i;
-	struct mod_kallsyms *kallsyms = rcu_dereference_sched(mod->kallsyms);
+	struct mod_kallsyms *kallsyms = rcu_dereference(mod->kallsyms);
 
 	for (i = 0; i < kallsyms->num_symtab; i++) {
 		const Elf_Sym *sym = &kallsyms->symtab[i];
@@ -447,24 +447,15 @@ static unsigned long __module_kallsyms_l
 /* Look for this name: can be of form module:name. */
 unsigned long module_kallsyms_lookup_name(const char *name)
 {
-	unsigned long ret;
-
 	/* Don't lock: we're in enough trouble already. */
 	guard(rcu)();
-	preempt_disable();
-	ret = __module_kallsyms_lookup_name(name);
-	preempt_enable();
-	return ret;
+	return __module_kallsyms_lookup_name(name);
 }
 
 unsigned long find_kallsyms_symbol_value(struct module *mod, const char *name)
 {
-	unsigned long ret;
-
-	preempt_disable();
-	ret = __find_kallsyms_symbol_value(mod, name);
-	preempt_enable();
-	return ret;
+	guard(rcu)();
+	return __find_kallsyms_symbol_value(mod, name);
 }
 
 int module_kallsyms_on_each_symbol(const char *modname,