From 85d2b0aa170351380be39fe4ff7973df1427fe76 Mon Sep 17 00:00:00 2001 From: Arnd Bergmann Date: Mon, 8 Apr 2024 10:05:58 +0200 Subject: [PATCH] module: don't ignore sysfs_create_link() failures The sysfs_create_link() return code is marked as __must_check, but the module_add_driver() function tries hard to not care, by assigning the return code to a variable. When building with 'make W=1', gcc still warns because this variable is only assigned but not used: drivers/base/module.c: In function 'module_add_driver': drivers/base/module.c:36:6: warning: variable 'no_warn' set but not used [-Wunused-but-set-variable] Rework the code to properly unwind and return the error code to the caller. My reading of the original code was that it tries to not fail when the links already exist, so keep ignoring -EEXIST errors. Fixes: e17e0f51aeea ("Driver core: show drivers in /sys/module/") See-also: 4a7fb6363f2d ("add __must_check to device management code") Signed-off-by: Arnd Bergmann Reviewed-by: Luis Chamberlain Link: https://lore.kernel.org/r/20240408080616.3911573-1-arnd@kernel.org Signed-off-by: Greg Kroah-Hartman --- drivers/base/base.h | 9 ++++++--- drivers/base/bus.c | 9 ++++++++- drivers/base/module.c | 42 +++++++++++++++++++++++++++++++----------- 3 files changed, 45 insertions(+), 15 deletions(-) diff --git a/drivers/base/base.h b/drivers/base/base.h index 0738ccad08b2e0..db4f910e8e36e9 100644 --- a/drivers/base/base.h +++ b/drivers/base/base.h @@ -192,11 +192,14 @@ extern struct kset *devices_kset; void devices_kset_move_last(struct device *dev); #if defined(CONFIG_MODULES) && defined(CONFIG_SYSFS) -void module_add_driver(struct module *mod, struct device_driver *drv); +int module_add_driver(struct module *mod, struct device_driver *drv); void module_remove_driver(struct device_driver *drv); #else -static inline void module_add_driver(struct module *mod, - struct device_driver *drv) { } +static inline int module_add_driver(struct module *mod, + struct device_driver *drv) +{ + return 0; +} static inline void module_remove_driver(struct device_driver *drv) { } #endif diff --git a/drivers/base/bus.c b/drivers/base/bus.c index daee55c9b2d9e1..ffea0728b8b2fb 100644 --- a/drivers/base/bus.c +++ b/drivers/base/bus.c @@ -674,7 +674,12 @@ int bus_add_driver(struct device_driver *drv) if (error) goto out_del_list; } - module_add_driver(drv->owner, drv); + error = module_add_driver(drv->owner, drv); + if (error) { + printk(KERN_ERR "%s: failed to create module links for %s\n", + __func__, drv->name); + goto out_detach; + } error = driver_create_file(drv, &driver_attr_uevent); if (error) { @@ -699,6 +704,8 @@ int bus_add_driver(struct device_driver *drv) return 0; +out_detach: + driver_detach(drv); out_del_list: klist_del(&priv->knode_bus); out_unregister: diff --git a/drivers/base/module.c b/drivers/base/module.c index 46ad4d636731dd..a1b55da07127d8 100644 --- a/drivers/base/module.c +++ b/drivers/base/module.c @@ -30,14 +30,14 @@ static void module_create_drivers_dir(struct module_kobject *mk) mutex_unlock(&drivers_dir_mutex); } -void module_add_driver(struct module *mod, struct device_driver *drv) +int module_add_driver(struct module *mod, struct device_driver *drv) { char *driver_name; - int no_warn; struct module_kobject *mk = NULL; + int ret; if (!drv) - return; + return 0; if (mod) mk = &mod->mkobj; @@ -56,17 +56,37 @@ void module_add_driver(struct module *mod, struct device_driver *drv) } if (!mk) - return; + return 0; + + ret = sysfs_create_link(&drv->p->kobj, &mk->kobj, "module"); + if (ret) + return ret; - /* Don't check return codes; these calls are idempotent */ - no_warn = sysfs_create_link(&drv->p->kobj, &mk->kobj, "module"); driver_name = make_driver_name(drv); - if (driver_name) { - module_create_drivers_dir(mk); - no_warn = sysfs_create_link(mk->drivers_dir, &drv->p->kobj, - driver_name); - kfree(driver_name); + if (!driver_name) { + ret = -ENOMEM; + goto out; + } + + module_create_drivers_dir(mk); + if (!mk->drivers_dir) { + ret = -EINVAL; + goto out; } + + ret = sysfs_create_link(mk->drivers_dir, &drv->p->kobj, driver_name); + if (ret) + goto out; + + kfree(driver_name); + + return 0; +out: + sysfs_remove_link(&drv->p->kobj, "module"); + sysfs_remove_link(mk->drivers_dir, driver_name); + kfree(driver_name); + + return ret; } void module_remove_driver(struct device_driver *drv)