From: Rafael J. Wysocki <rjw@xxxxxxx> Use a hibernation and suspend notifier to disable the user mode helper before a hibernation/suspend and enable it after the operation. Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx> kernel/kmod.c | 31 +++++++++++++++++++++++++++++-- 1 file changed, 29 insertions(+), 2 deletions(-) Index: linux-2.6.22-rc3/kernel/kmod.c =================================================================== --- linux-2.6.22-rc3.orig/kernel/kmod.c 2007-05-27 18:56:44.000000000 +0200 +++ linux-2.6.22-rc3/kernel/kmod.c 2007-05-27 19:43:35.000000000 +0200 @@ -33,6 +33,8 @@ #include <linux/kernel.h> #include <linux/init.h> #include <linux/resource.h> +#include <linux/notifier.h> +#include <linux/suspend.h> #include <asm/uaccess.h> extern int max_threads; @@ -46,6 +48,14 @@ static struct workqueue_struct *khelper_ */ char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe"; +/* + * If set, both call_usermodehelper_keys() and call_usermodehelper_pipe() exit + * immediately returning -EBUSY. Used for preventing user land processes from + * being created after the user land has been frozen during a system-wide + * hibernation or suspend operation. + */ +static int usermodehelper_disabled; + /** * request_module - try to load a kernel module * @fmt: printf style format string for the name of the module @@ -251,6 +261,22 @@ static void __call_usermodehelper(struct complete(sub_info->complete); } +static int usermodehelper_pm_callback(struct notifier_block *nfb, + unsigned long action, + void *ignored) +{ + switch (action) { + case PM_PRE_FREEZE: + usermodehelper_disabled = 1; + return NOTIFY_OK; + case PM_POST_THAW: + usermodehelper_disabled = 0; + return NOTIFY_OK; + } + + return NOTIFY_DONE; +} + /** * call_usermodehelper_keys - start a usermode application * @path: pathname for the application @@ -276,7 +302,7 @@ int call_usermodehelper_keys(char *path, struct subprocess_info *sub_info; int retval; - if (!khelper_wq) + if (!khelper_wq || usermodehelper_disabled) return -EBUSY; if (path[0] == '\0') @@ -319,7 +345,7 @@ int call_usermodehelper_pipe(char *path, }; struct file *f; - if (!khelper_wq) + if (!khelper_wq || usermodehelper_disabled) return -EBUSY; if (path[0] == '\0') @@ -347,4 +373,5 @@ void __init usermodehelper_init(void) { khelper_wq = create_singlethread_workqueue("khelper"); BUG_ON(!khelper_wq); + pm_notifier(usermodehelper_pm_callback, 0); } _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm