linux-kernel - [v1 3/3] drivers: base: handle module

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Message-Id: <20250204052222.1611510-4-shyamsaini@linux.microsoft.com>
Date: Mon,  3 Feb 2025 21:22:22 -0800
From: Shyam Saini <shyamsaini@...ux.microsoft.com>
To: linux-kernel@...r.kernel.org,
	linux-modules@...r.kernel.org
Cc: code@...icks.com,
	linux@...musvillemoes.dk,
	mcgrof@...nel.org,
	frkaya@...ux.microsoft.com,
	vijayb@...ux.microsoft.com,
	petr.pavlu@...e.com,
	linux@...ssschuh.net,
	samitolvanen@...gle.com,
	da.gomez@...sung.com,
	gregkh@...uxfoundation.org,
	rafael@...nel.org,
	dakr@...nel.org
Subject: [v1 3/3] drivers: base: handle module_kboject creation

module_add_driver() relies on module_kset list for
/sys/module/<built-in-module>/drivers directory creation.

Since,
commit 96a1a2412acb ("kernel/params.c: defer most of param_sysfs_init() to late_initcall time")
drivers which are initialized from subsys_initcall() or any other
higher precedence initcall couldn't find the related kobject entry
in the module_kset list because module_kset is not fully populated
by the time module_add_driver() refers it. As a consequence,
module_add_driver() returns early without calling make_driver_name().
Therefore, /sys/module/<built-in-module>/drivers is never created.

Fix this issue by letting module_add_driver() handle module_kobject
creation itself.

Fixes: 96a1a2412acb ("kernel/params.c: defer most of param_sysfs_init() to late_initcall time")
Suggested-by: Rasmus Villemoes <linux@...musvillemoes.dk>
Signed-off-by: Shyam Saini <shyamsaini@...ux.microsoft.com>
---
 drivers/base/module.c | 13 +++++--------
 1 file changed, 5 insertions(+), 8 deletions(-)

diff --git a/drivers/base/module.c b/drivers/base/module.c
index 5bc71bea883a..218aaa096455 100644
--- a/drivers/base/module.c
+++ b/drivers/base/module.c
@@ -42,16 +42,13 @@ int module_add_driver(struct module *mod, const struct device_driver *drv)
 	if (mod)
 		mk = &mod->mkobj;
 	else if (drv->mod_name) {
-		struct kobject *mkobj;
-
-		/* Lookup built-in module entry in /sys/modules */
-		mkobj = kset_find_obj(module_kset, drv->mod_name);
-		if (mkobj) {
-			mk = container_of(mkobj, struct module_kobject, kobj);
+		/* Lookup or create built-in module entry in /sys/modules */
+		mk = lookup_or_create_module_kobject(drv->mod_name);
+		if (mk) {
 			/* remember our module structure */
 			drv->p->mkobj = mk;
-			/* kset_find_obj took a reference */
-			kobject_put(mkobj);
+			/* lookup_or_create_module_kobject took a reference */
+			kobject_put(&mk->kobj);
 		}
 	}
 
-- 
2.34.1