@@ -663,7 +663,7 @@ static inline bool within_module(unsigned long addr, const struct module *mod)
return within_module_init(addr, mod) || within_module_core(addr, mod);
}
-/* Search for module by name: must be in a RCU-sched critical section. */
+/* Search for module by name: must be in a RCU critical section. */
struct module *find_module(const char *name);
extern void __noreturn __module_put_and_kthread_exit(struct module *mod,
@@ -59,7 +59,7 @@ static void klp_find_object_module(struct klp_object *obj)
if (!klp_is_module(obj))
return;
- rcu_read_lock_sched();
+ guard(rcu)();
/*
* We do not want to block removal of patched modules and therefore
* we do not take a reference here. The patches are removed by
@@ -75,8 +75,6 @@ static void klp_find_object_module(struct klp_object *obj)
*/
if (mod && mod->klp_alive)
obj->mod = mod;
-
- rcu_read_unlock_sched();
}
static bool klp_initialized(void)
@@ -450,6 +450,7 @@ 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();
@@ -374,16 +374,14 @@ bool find_symbol(struct find_symbol_arg *fsa)
}
/*
- * Search for module by name: must hold module_mutex (or preempt disabled
- * for read-only access).
+ * Search for module by name: must hold module_mutex (or RCU for read-only
+ * access).
*/
struct module *find_module_all(const char *name, size_t len,
bool even_unformed)
{
struct module *mod;
- module_assert_mutex_or_preempt();
-
list_for_each_entry_rcu(mod, &modules, list,
lockdep_is_held(&module_mutex)) {
if (!even_unformed && mod->state == MODULE_STATE_UNFORMED)
@@ -123,9 +123,8 @@ static nokprobe_inline bool trace_kprobe_module_exist(struct trace_kprobe *tk)
if (!p)
return true;
*p = '\0';
- rcu_read_lock_sched();
- ret = !!find_module(tk->symbol);
- rcu_read_unlock_sched();
+ scoped_guard(rcu)
+ ret = !!find_module(tk->symbol);
*p = ':';
return ret;
@@ -800,12 +799,10 @@ static struct module *try_module_get_by_name(const char *name)
{
struct module *mod;
- rcu_read_lock_sched();
+ guard(rcu)();
mod = find_module(name);
if (mod && !try_module_get(mod))
mod = NULL;
- rcu_read_unlock_sched();
-
return mod;
}
#else
The modules list and module::kallsyms can be accessed under RCU assumption. Remove module_assert_mutex_or_preempt() from find_module_all() so it can be used under RCU protection without warnings. Update its callers to use RCU protection instead of preempt_disable(). Cc: Jiri Kosina <jikos@kernel.org> Cc: Joe Lawrence <joe.lawrence@redhat.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Cc: Miroslav Benes <mbenes@suse.cz> Cc: Petr Mladek <pmladek@suse.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: linux-trace-kernel@vger.kernel.org Cc: live-patching@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> --- include/linux/module.h | 2 +- kernel/livepatch/core.c | 4 +--- kernel/module/kallsyms.c | 1 + kernel/module/main.c | 6 ++---- kernel/trace/trace_kprobe.c | 9 +++------ 5 files changed, 8 insertions(+), 14 deletions(-)