From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9ADEB29CEA; Mon, 8 Apr 2024 08:06:22 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712563582; cv=none; b=MqUXX8T45H9EXQ3OLB5VeIcJU8+LcaVga11O/BVEsD9oJcPQMl6hKUGPf05aK8Ia2WcRfQRIqDEwPirI0ZDiihxECWZcQpsx62LldePllfCT6uiafabsFoX2rpFCjgVzigOsqG9IEJzJGNY/x+pieo7wQVQiqs+A8zE1eBPVvVk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1712563582; c=relaxed/simple; bh=TX+FD3p3l4+7566GyF6jvv4HQftl4YsdRmMDigxumnI=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=bHS2Md8K5wTEFOmuzq92nYCy8nTSCi3AKlJY+KUh3C+n7iRahxZQGZaRopAyh7kSZZ2QcmHld5jvr8MJauYgzV2F8K4LY1Cg0wMqZn6V659/cIo+NLEg5zkr0sUVWQ88HSK/Ubsd9qFKxYDW+ApOre5HKt/LvZ2g5Gv3WsV2NZ8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=envx6Q6E; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="envx6Q6E" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 88523C433C7; Mon, 8 Apr 2024 08:06:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1712563582; bh=TX+FD3p3l4+7566GyF6jvv4HQftl4YsdRmMDigxumnI=; h=From:To:Cc:Subject:Date:From; b=envx6Q6EeNU7r/yDittBuydlGFZHg1q9TRqI3a8eYuSgjFbvPSjV9GkUQI9DK1NKn SLcEDCGzL+6XMElann/g66gzeMHFuAz9zS7DzRwe72KIsDeMShgTJMINGjAGRmKXic 5DQJDWTFTw/QBf9cnYnPt5Zz078eeHUmJa74t/RRXhkkrs34XcRGbcnrhJ0gWkZ0jV YKfKCMdHOPm8nwXO9r8Zzv2zQFLaQIa7y0pE50v2up1ubs4qF8XOo5wkY6RcVNDEIL qaCvA0veEG4oK7qjfW75lXK6cOiZXJ08LF48K+F5hAoRp34vx9pdG0GqOyu8qdhFsk KGEe9X7cVgxwA== From: Arnd Bergmann To: Luis Chamberlain Cc: Arnd Bergmann , Greg Kroah-Hartman , linux-modules@vger.kernel.org, "Rafael J. Wysocki" , Jens Axboe , linux-kernel@vger.kernel.org Subject: [PATCH] [v4] module: don't ignore sysfs_create_link() failures Date: Mon, 8 Apr 2024 10:05:58 +0200 Message-Id: <20240408080616.3911573-1-arnd@kernel.org> X-Mailer: git-send-email 2.39.2 Precedence: bulk X-Mailing-List: linux-modules@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Arnd Bergmann 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/") Reviewed-by: Greg Kroah-Hartman See-also: 4a7fb6363f2d ("add __must_check to device management code") Signed-off-by: Arnd Bergmann --- Luis, can you merge this through the modules-next tree? Cc: Luis Chamberlain Cc: linux-modules@vger.kernel.org Cc: "Rafael J. Wysocki" --- v4: minor style changes, based on feedback from Andy Shevchenko v3: make error handling stricter, add unwinding, fix build fail with CONFIG_MODULES=n v2: rework to actually handle the error. I have not tested the error handling beyond build testing, so please review carefully. --- 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 0738ccad08b2..db4f910e8e36 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 daee55c9b2d9..ffea0728b8b2 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 46ad4d636731..a1b55da07127 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) -- 2.39.2