The module_wq wait queue has only non-exclusive waiters and all waits
are interruptible, therefore for consistency use wake_up_interruptible()
to wake its waiters.

Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
---
 kernel/module/main.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/module/main.c b/kernel/module/main.c
index a4e4d84b6f4e..06cb41c3d2a1 100644
--- a/kernel/module/main.c
+++ b/kernel/module/main.c
@@ -763,7 +763,7 @@ SYSCALL_DEFINE2(delete_module, const char __user *, name_user,
 
 	free_module(mod);
 	/* someone could wait for the module in add_unformed_module() */
-	wake_up_all(&module_wq);
+	wake_up_interruptible(&module_wq);
 	return 0;
 out:
 	mutex_unlock(&module_mutex);
@@ -2524,7 +2524,7 @@ static noinline int do_init_module(struct module *mod)
 		schedule_work(&init_free_wq);
 
 	mutex_unlock(&module_mutex);
-	wake_up_all(&module_wq);
+	wake_up_interruptible(&module_wq);
 
 	return 0;
 
@@ -2540,7 +2540,7 @@ static noinline int do_init_module(struct module *mod)
 	klp_module_going(mod);
 	ftrace_release_mod(mod);
 	free_module(mod);
-	wake_up_all(&module_wq);
+	wake_up_interruptible(&module_wq);
 	return ret;
 }
 
@@ -2886,7 +2886,7 @@ static int load_module(struct load_info *info, const char __user *uargs,
 	/* Unlink carefully: kallsyms could be walking list. */
 	list_del_rcu(&mod->list);
 	mod_tree_remove(mod);
-	wake_up_all(&module_wq);
+	wake_up_interruptible(&module_wq);
 	/* Wait for RCU-sched synchronizing before releasing mod->list. */
 	synchronize_rcu();
 	mutex_unlock(&module_mutex);
-- 
2.35.3

On Mon, Sep 19, 2022 at 02:32:32PM +0200, Petr Pavlu wrote:
> The module_wq wait queue has only non-exclusive waiters and all waits
> are interruptible, therefore for consistency use wake_up_interruptible()
> to wake its waiters.
> 
> Suggested-by: Petr Mladek <pmladek@suse.com>
> Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>

Does this fix a bug? It seems like it does. Please think of this should
go to stable, for instance, does it fix a bug not yet reported?

  Luis

On Fri 2022-09-30 13:22:25, Luis Chamberlain wrote:
> On Mon, Sep 19, 2022 at 02:32:32PM +0200, Petr Pavlu wrote:
> > The module_wq wait queue has only non-exclusive waiters and all waits
> > are interruptible, therefore for consistency use wake_up_interruptible()
> > to wake its waiters.
> > 
> > Suggested-by: Petr Mladek <pmladek@suse.com>
> > Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>
> 
> Does this fix a bug? It seems like it does. Please think of this should
> go to stable, for instance, does it fix a bug not yet reported?

It is rather a clean up. It should not change the existing behavior.

wake_up_all() is needed only in special situations when
exclusive waiters are used. Also wake_up_*() variant should match
the related wait_for_completion_*() variants.

The patch looks good:

Reviewed-by: Petr Mladek <pmladek@suse.com>

Best Regards,
Petr