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https://github.com/torvalds/linux
synced 2024-09-06 18:01:05 +00:00
Driver core: let request_module() send a /sys/modules/kmod/-uevent
On recent systems, calls to /sbin/modprobe are handled by udev depending on the kind of device the kernel has discovered. This patch creates an uevent for the kernels internal request_module(), to let udev take control over the request, instead of forking the binary directly by the kernel. The direct execution of /sbin/modprobe can be disabled by setting: /sys/module/kmod/mod_request_helper (/proc/sys/kernel/modprobe) to an empty string, the same way /proc/sys/kernel/hotplug is disabled on an udev system. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
parent
89790fd789
commit
c353c3fb07
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@ -28,8 +28,10 @@
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#ifdef CONFIG_KMOD
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/* modprobe exit status on success, -ve on error. Return value
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* usually useless though. */
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extern void kmod_sysfs_init(void);
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extern int request_module(const char * name, ...) __attribute__ ((format (printf, 1, 2)));
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#else
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static inline void kmod_sysfs_init(void) {};
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static inline int request_module(const char * name, ...) { return -ENOSYS; }
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#endif
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120
kernel/kmod.c
120
kernel/kmod.c
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@ -36,6 +36,8 @@
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#include <linux/resource.h>
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#include <asm/uaccess.h>
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extern int delete_module(const char *name, unsigned int flags);
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extern int max_threads;
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static struct workqueue_struct *khelper_wq;
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@ -46,6 +48,7 @@ static struct workqueue_struct *khelper_wq;
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modprobe_path is set via /proc/sys.
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*/
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char modprobe_path[KMOD_PATH_LEN] = "/sbin/modprobe";
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struct module_kobject kmod_mk;
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/**
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* request_module - try to load a kernel module
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@ -75,6 +78,11 @@ int request_module(const char *fmt, ...)
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static atomic_t kmod_concurrent = ATOMIC_INIT(0);
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#define MAX_KMOD_CONCURRENT 50 /* Completely arbitrary value - KAO */
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static int kmod_loop_msg;
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char modalias[16 + MODULE_NAME_LEN] = "MODALIAS=";
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char *uevent_envp[2] = {
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modalias,
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NULL
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};
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va_start(args, fmt);
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ret = vsnprintf(module_name, MODULE_NAME_LEN, fmt, args);
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@ -82,6 +90,12 @@ int request_module(const char *fmt, ...)
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if (ret >= MODULE_NAME_LEN)
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return -ENAMETOOLONG;
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strcpy(&modalias[strlen("MODALIAS=")], module_name);
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kobject_uevent_env(&kmod_mk.kobj, KOBJ_CHANGE, uevent_envp);
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if (modprobe_path[0] == '\0')
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goto out;
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/* If modprobe needs a service that is in a module, we get a recursive
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* loop. Limit the number of running kmod threads to max_threads/2 or
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* MAX_KMOD_CONCURRENT, whichever is the smaller. A cleaner method
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@ -108,9 +122,115 @@ int request_module(const char *fmt, ...)
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ret = call_usermodehelper(modprobe_path, argv, envp, 1);
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atomic_dec(&kmod_concurrent);
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out:
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return ret;
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}
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EXPORT_SYMBOL(request_module);
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static ssize_t store_mod_request(struct module_attribute *mattr,
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struct module *mod,
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const char *buffer, size_t count)
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{
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char name[MODULE_NAME_LEN];
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int ret;
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if (count < 1 || count+1 > MODULE_NAME_LEN)
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return -EINVAL;
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memcpy(name, buffer, count);
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name[count] = '\0';
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if (name[count-1] == '\n')
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name[count-1] = '\0';
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ret = request_module(name);
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if (ret < 0)
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return ret;
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return count;
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}
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static struct module_attribute mod_request = {
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.attr = { .name = "mod_request", .mode = S_IWUSR, .owner = THIS_MODULE },
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.store = store_mod_request,
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};
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#ifdef CONFIG_MODULE_UNLOAD
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static ssize_t store_mod_unload(struct module_attribute *mattr,
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struct module *mod,
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const char *buffer, size_t count)
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{
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char name[MODULE_NAME_LEN];
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int ret;
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if (count < 1 || count+1 > MODULE_NAME_LEN)
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return -EINVAL;
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memcpy(name, buffer, count);
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name[count] = '\0';
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if (name[count-1] == '\n')
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name[count-1] = '\0';
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ret = delete_module(name, O_NONBLOCK);
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if (ret < 0)
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return ret;
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return count;
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}
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static struct module_attribute mod_unload = {
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.attr = { .name = "mod_unload", .mode = S_IWUSR, .owner = THIS_MODULE },
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.store = store_mod_unload,
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};
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#endif
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static ssize_t show_mod_request_helper(struct module_attribute *mattr,
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struct module *mod,
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char *buffer)
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{
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return sprintf(buffer, "%s\n", modprobe_path);
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}
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static ssize_t store_mod_request_helper(struct module_attribute *mattr,
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struct module *mod,
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const char *buffer, size_t count)
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{
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if (count < 1 || count+1 > KMOD_PATH_LEN)
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return -EINVAL;
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memcpy(modprobe_path, buffer, count);
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modprobe_path[count] = '\0';
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if (modprobe_path[count-1] == '\n')
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modprobe_path[count-1] = '\0';
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return count;
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}
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static struct module_attribute mod_request_helper = {
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.attr = {
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.name = "mod_request_helper",
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.mode = S_IWUSR | S_IRUGO,
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.owner = THIS_MODULE
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},
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.show = show_mod_request_helper,
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.store = store_mod_request_helper,
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};
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void __init kmod_sysfs_init(void)
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{
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int ret;
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kmod_mk.mod = THIS_MODULE;
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kobj_set_kset_s(&kmod_mk, module_subsys);
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kobject_set_name(&kmod_mk.kobj, "kmod");
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kobject_init(&kmod_mk.kobj);
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ret = kobject_add(&kmod_mk.kobj);
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if (ret < 0)
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goto out;
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ret = sysfs_create_file(&kmod_mk.kobj, &mod_request_helper.attr);
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ret = sysfs_create_file(&kmod_mk.kobj, &mod_request.attr);
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#ifdef CONFIG_MODULE_UNLOAD
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ret = sysfs_create_file(&kmod_mk.kobj, &mod_unload.attr);
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#endif
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kobject_uevent(&kmod_mk.kobj, KOBJ_ADD);
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out:
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return;
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}
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#endif /* CONFIG_KMOD */
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struct subprocess_info {
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@ -653,20 +653,11 @@ static void wait_for_zero_refcount(struct module *mod)
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mutex_lock(&module_mutex);
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}
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asmlinkage long
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sys_delete_module(const char __user *name_user, unsigned int flags)
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int delete_module(const char *name, unsigned int flags)
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{
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struct module *mod;
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char name[MODULE_NAME_LEN];
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int ret, forced = 0;
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if (!capable(CAP_SYS_MODULE))
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return -EPERM;
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if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
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return -EFAULT;
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name[MODULE_NAME_LEN-1] = '\0';
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if (mutex_lock_interruptible(&module_mutex) != 0)
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return -EINTR;
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return ret;
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}
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asmlinkage long
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sys_delete_module(const char __user *name_user, unsigned int flags)
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{
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char name[MODULE_NAME_LEN];
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if (!capable(CAP_SYS_MODULE))
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return -EPERM;
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if (strncpy_from_user(name, name_user, MODULE_NAME_LEN-1) < 0)
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return -EFAULT;
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name[MODULE_NAME_LEN-1] = '\0';
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return delete_module(name, flags);
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}
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static void print_unload_info(struct seq_file *m, struct module *mod)
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{
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struct module_use *use;
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@ -714,6 +714,7 @@ static int __init param_sysfs_init(void)
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}
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param_sysfs_builtin();
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kmod_sysfs_init();
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return 0;
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}
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