1 /*
2 * taskstats.c - Export per-task statistics to userland
3 *
4 * Copyright (C) Shailabh Nagar, IBM Corp. 2006
5 * (C) Balbir Singh, IBM Corp. 2006
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License as published by
9 * the Free Software Foundation; either version 2 of the License, or
10 * (at your option) any later version.
11 *
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
16 *
17 */
18
19 #include <linux/kernel.h>
20 #include <linux/taskstats_kern.h>
21 #include <linux/tsacct_kern.h>
22 #include <linux/delayacct.h>
23 #include <linux/cpumask.h>
24 #include <linux/percpu.h>
25 #include <linux/slab.h>
26 #include <linux/cgroupstats.h>
27 #include <linux/cgroup.h>
28 #include <linux/fs.h>
29 #include <linux/file.h>
30 #include <linux/pid_namespace.h>
31 #include <net/genetlink.h>
32 #include <linux/atomic.h>
33
34 /*
35 * Maximum length of a cpumask that can be specified in
36 * the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute
37 */
38 #define TASKSTATS_CPUMASK_MAXLEN (100+6*NR_CPUS)
39
40 static DEFINE_PER_CPU(__u32, taskstats_seqnum);
41 static int family_registered;
42 struct kmem_cache *taskstats_cache;
43
44 static struct genl_family family = {
45 .id = GENL_ID_GENERATE,
46 .name = TASKSTATS_GENL_NAME,
47 .version = TASKSTATS_GENL_VERSION,
48 .maxattr = TASKSTATS_CMD_ATTR_MAX,
49 };
50
51 static const struct nla_policy taskstats_cmd_get_policy[TASKSTATS_CMD_ATTR_MAX+1] = {
52 [TASKSTATS_CMD_ATTR_PID] = { .type = NLA_U32 },
53 [TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 },
54 [TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
55 [TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};
56
57 static const struct nla_policy cgroupstats_cmd_get_policy[CGROUPSTATS_CMD_ATTR_MAX+1] = {
58 [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },
59 };
60
61 struct listener {
62 struct list_head list;
63 pid_t pid;
64 char valid;
65 };
66
67 struct listener_list {
68 struct rw_semaphore sem;
69 struct list_head list;
70 };
71 static DEFINE_PER_CPU(struct listener_list, listener_array);
72
73 enum actions {
74 REGISTER,
75 DEREGISTER,
76 CPU_DONT_CARE
77 };
78
prepare_reply(struct genl_info * info,u8 cmd,struct sk_buff ** skbp,size_t size)79 static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
80 size_t size)
81 {
82 struct sk_buff *skb;
83 void *reply;
84
85 /*
86 * If new attributes are added, please revisit this allocation
87 */
88 skb = genlmsg_new(size, GFP_KERNEL);
89 if (!skb)
90 return -ENOMEM;
91
92 if (!info) {
93 int seq = this_cpu_inc_return(taskstats_seqnum) - 1;
94
95 reply = genlmsg_put(skb, 0, seq, &family, 0, cmd);
96 } else
97 reply = genlmsg_put_reply(skb, info, &family, 0, cmd);
98 if (reply == NULL) {
99 nlmsg_free(skb);
100 return -EINVAL;
101 }
102
103 *skbp = skb;
104 return 0;
105 }
106
107 /*
108 * Send taskstats data in @skb to listener with nl_pid @pid
109 */
send_reply(struct sk_buff * skb,struct genl_info * info)110 static int send_reply(struct sk_buff *skb, struct genl_info *info)
111 {
112 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
113 void *reply = genlmsg_data(genlhdr);
114 int rc;
115
116 rc = genlmsg_end(skb, reply);
117 if (rc < 0) {
118 nlmsg_free(skb);
119 return rc;
120 }
121
122 return genlmsg_reply(skb, info);
123 }
124
125 /*
126 * Send taskstats data in @skb to listeners registered for @cpu's exit data
127 */
send_cpu_listeners(struct sk_buff * skb,struct listener_list * listeners)128 static void send_cpu_listeners(struct sk_buff *skb,
129 struct listener_list *listeners)
130 {
131 struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
132 struct listener *s, *tmp;
133 struct sk_buff *skb_next, *skb_cur = skb;
134 void *reply = genlmsg_data(genlhdr);
135 int rc, delcount = 0;
136
137 rc = genlmsg_end(skb, reply);
138 if (rc < 0) {
139 nlmsg_free(skb);
140 return;
141 }
142
143 rc = 0;
144 down_read(&listeners->sem);
145 list_for_each_entry(s, &listeners->list, list) {
146 skb_next = NULL;
147 if (!list_is_last(&s->list, &listeners->list)) {
148 skb_next = skb_clone(skb_cur, GFP_KERNEL);
149 if (!skb_next)
150 break;
151 }
152 rc = genlmsg_unicast(&init_net, skb_cur, s->pid);
153 if (rc == -ECONNREFUSED) {
154 s->valid = 0;
155 delcount++;
156 }
157 skb_cur = skb_next;
158 }
159 up_read(&listeners->sem);
160
161 if (skb_cur)
162 nlmsg_free(skb_cur);
163
164 if (!delcount)
165 return;
166
167 /* Delete invalidated entries */
168 down_write(&listeners->sem);
169 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
170 if (!s->valid) {
171 list_del(&s->list);
172 kfree(s);
173 }
174 }
175 up_write(&listeners->sem);
176 }
177
fill_stats(struct user_namespace * user_ns,struct pid_namespace * pid_ns,struct task_struct * tsk,struct taskstats * stats)178 static void fill_stats(struct user_namespace *user_ns,
179 struct pid_namespace *pid_ns,
180 struct task_struct *tsk, struct taskstats *stats)
181 {
182 memset(stats, 0, sizeof(*stats));
183 /*
184 * Each accounting subsystem adds calls to its functions to
185 * fill in relevant parts of struct taskstsats as follows
186 *
187 * per-task-foo(stats, tsk);
188 */
189
190 delayacct_add_tsk(stats, tsk);
191
192 /* fill in basic acct fields */
193 stats->version = TASKSTATS_VERSION;
194 stats->nvcsw = tsk->nvcsw;
195 stats->nivcsw = tsk->nivcsw;
196 bacct_add_tsk(user_ns, pid_ns, stats, tsk);
197
198 /* fill in extended acct fields */
199 xacct_add_tsk(stats, tsk);
200 }
201
fill_stats_for_pid(pid_t pid,struct taskstats * stats)202 static int fill_stats_for_pid(pid_t pid, struct taskstats *stats)
203 {
204 struct task_struct *tsk;
205
206 rcu_read_lock();
207 tsk = find_task_by_vpid(pid);
208 if (tsk)
209 get_task_struct(tsk);
210 rcu_read_unlock();
211 if (!tsk)
212 return -ESRCH;
213 fill_stats(current_user_ns(), task_active_pid_ns(current), tsk, stats);
214 put_task_struct(tsk);
215 return 0;
216 }
217
fill_stats_for_tgid(pid_t tgid,struct taskstats * stats)218 static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats)
219 {
220 struct task_struct *tsk, *first;
221 unsigned long flags;
222 int rc = -ESRCH;
223
224 /*
225 * Add additional stats from live tasks except zombie thread group
226 * leaders who are already counted with the dead tasks
227 */
228 rcu_read_lock();
229 first = find_task_by_vpid(tgid);
230
231 if (!first || !lock_task_sighand(first, &flags))
232 goto out;
233
234 if (first->signal->stats)
235 memcpy(stats, first->signal->stats, sizeof(*stats));
236 else
237 memset(stats, 0, sizeof(*stats));
238
239 tsk = first;
240 do {
241 if (tsk->exit_state)
242 continue;
243 /*
244 * Accounting subsystem can call its functions here to
245 * fill in relevant parts of struct taskstsats as follows
246 *
247 * per-task-foo(stats, tsk);
248 */
249 delayacct_add_tsk(stats, tsk);
250
251 stats->nvcsw += tsk->nvcsw;
252 stats->nivcsw += tsk->nivcsw;
253 } while_each_thread(first, tsk);
254
255 unlock_task_sighand(first, &flags);
256 rc = 0;
257 out:
258 rcu_read_unlock();
259
260 stats->version = TASKSTATS_VERSION;
261 /*
262 * Accounting subsystems can also add calls here to modify
263 * fields of taskstats.
264 */
265 return rc;
266 }
267
fill_tgid_exit(struct task_struct * tsk)268 static void fill_tgid_exit(struct task_struct *tsk)
269 {
270 unsigned long flags;
271
272 spin_lock_irqsave(&tsk->sighand->siglock, flags);
273 if (!tsk->signal->stats)
274 goto ret;
275
276 /*
277 * Each accounting subsystem calls its functions here to
278 * accumalate its per-task stats for tsk, into the per-tgid structure
279 *
280 * per-task-foo(tsk->signal->stats, tsk);
281 */
282 delayacct_add_tsk(tsk->signal->stats, tsk);
283 ret:
284 spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
285 return;
286 }
287
add_del_listener(pid_t pid,const struct cpumask * mask,int isadd)288 static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
289 {
290 struct listener_list *listeners;
291 struct listener *s, *tmp, *s2;
292 unsigned int cpu;
293
294 if (!cpumask_subset(mask, cpu_possible_mask))
295 return -EINVAL;
296
297 if (current_user_ns() != &init_user_ns)
298 return -EINVAL;
299
300 if (task_active_pid_ns(current) != &init_pid_ns)
301 return -EINVAL;
302
303 if (isadd == REGISTER) {
304 for_each_cpu(cpu, mask) {
305 s = kmalloc_node(sizeof(struct listener),
306 GFP_KERNEL, cpu_to_node(cpu));
307 if (!s)
308 goto cleanup;
309
310 s->pid = pid;
311 s->valid = 1;
312
313 listeners = &per_cpu(listener_array, cpu);
314 down_write(&listeners->sem);
315 list_for_each_entry(s2, &listeners->list, list) {
316 if (s2->pid == pid && s2->valid)
317 goto exists;
318 }
319 list_add(&s->list, &listeners->list);
320 s = NULL;
321 exists:
322 up_write(&listeners->sem);
323 kfree(s); /* nop if NULL */
324 }
325 return 0;
326 }
327
328 /* Deregister or cleanup */
329 cleanup:
330 for_each_cpu(cpu, mask) {
331 listeners = &per_cpu(listener_array, cpu);
332 down_write(&listeners->sem);
333 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
334 if (s->pid == pid) {
335 list_del(&s->list);
336 kfree(s);
337 break;
338 }
339 }
340 up_write(&listeners->sem);
341 }
342 return 0;
343 }
344
parse(struct nlattr * na,struct cpumask * mask)345 static int parse(struct nlattr *na, struct cpumask *mask)
346 {
347 char *data;
348 int len;
349 int ret;
350
351 if (na == NULL)
352 return 1;
353 len = nla_len(na);
354 if (len > TASKSTATS_CPUMASK_MAXLEN)
355 return -E2BIG;
356 if (len < 1)
357 return -EINVAL;
358 data = kmalloc(len, GFP_KERNEL);
359 if (!data)
360 return -ENOMEM;
361 nla_strlcpy(data, na, len);
362 ret = cpulist_parse(data, mask);
363 kfree(data);
364 return ret;
365 }
366
367 #if defined(CONFIG_64BIT) && !defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS)
368 #define TASKSTATS_NEEDS_PADDING 1
369 #endif
370
mk_reply(struct sk_buff * skb,int type,u32 pid)371 static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
372 {
373 struct nlattr *na, *ret;
374 int aggr;
375
376 aggr = (type == TASKSTATS_TYPE_PID)
377 ? TASKSTATS_TYPE_AGGR_PID
378 : TASKSTATS_TYPE_AGGR_TGID;
379
380 /*
381 * The taskstats structure is internally aligned on 8 byte
382 * boundaries but the layout of the aggregrate reply, with
383 * two NLA headers and the pid (each 4 bytes), actually
384 * force the entire structure to be unaligned. This causes
385 * the kernel to issue unaligned access warnings on some
386 * architectures like ia64. Unfortunately, some software out there
387 * doesn't properly unroll the NLA packet and assumes that the start
388 * of the taskstats structure will always be 20 bytes from the start
389 * of the netlink payload. Aligning the start of the taskstats
390 * structure breaks this software, which we don't want. So, for now
391 * the alignment only happens on architectures that require it
392 * and those users will have to update to fixed versions of those
393 * packages. Space is reserved in the packet only when needed.
394 * This ifdef should be removed in several years e.g. 2012 once
395 * we can be confident that fixed versions are installed on most
396 * systems. We add the padding before the aggregate since the
397 * aggregate is already a defined type.
398 */
399 #ifdef TASKSTATS_NEEDS_PADDING
400 if (nla_put(skb, TASKSTATS_TYPE_NULL, 0, NULL) < 0)
401 goto err;
402 #endif
403 na = nla_nest_start(skb, aggr);
404 if (!na)
405 goto err;
406
407 if (nla_put(skb, type, sizeof(pid), &pid) < 0)
408 goto err;
409 ret = nla_reserve(skb, TASKSTATS_TYPE_STATS, sizeof(struct taskstats));
410 if (!ret)
411 goto err;
412 nla_nest_end(skb, na);
413
414 return nla_data(ret);
415 err:
416 return NULL;
417 }
418
cgroupstats_user_cmd(struct sk_buff * skb,struct genl_info * info)419 static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
420 {
421 int rc = 0;
422 struct sk_buff *rep_skb;
423 struct cgroupstats *stats;
424 struct nlattr *na;
425 size_t size;
426 u32 fd;
427 struct fd f;
428
429 na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
430 if (!na)
431 return -EINVAL;
432
433 fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);
434 f = fdget(fd);
435 if (!f.file)
436 return 0;
437
438 size = nla_total_size(sizeof(struct cgroupstats));
439
440 rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb,
441 size);
442 if (rc < 0)
443 goto err;
444
445 na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS,
446 sizeof(struct cgroupstats));
447 if (na == NULL) {
448 nlmsg_free(rep_skb);
449 rc = -EMSGSIZE;
450 goto err;
451 }
452
453 stats = nla_data(na);
454 memset(stats, 0, sizeof(*stats));
455
456 rc = cgroupstats_build(stats, f.file->f_dentry);
457 if (rc < 0) {
458 nlmsg_free(rep_skb);
459 goto err;
460 }
461
462 rc = send_reply(rep_skb, info);
463
464 err:
465 fdput(f);
466 return rc;
467 }
468
cmd_attr_register_cpumask(struct genl_info * info)469 static int cmd_attr_register_cpumask(struct genl_info *info)
470 {
471 cpumask_var_t mask;
472 int rc;
473
474 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
475 return -ENOMEM;
476 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask);
477 if (rc < 0)
478 goto out;
479 rc = add_del_listener(info->snd_portid, mask, REGISTER);
480 out:
481 free_cpumask_var(mask);
482 return rc;
483 }
484
cmd_attr_deregister_cpumask(struct genl_info * info)485 static int cmd_attr_deregister_cpumask(struct genl_info *info)
486 {
487 cpumask_var_t mask;
488 int rc;
489
490 if (!alloc_cpumask_var(&mask, GFP_KERNEL))
491 return -ENOMEM;
492 rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask);
493 if (rc < 0)
494 goto out;
495 rc = add_del_listener(info->snd_portid, mask, DEREGISTER);
496 out:
497 free_cpumask_var(mask);
498 return rc;
499 }
500
taskstats_packet_size(void)501 static size_t taskstats_packet_size(void)
502 {
503 size_t size;
504
505 size = nla_total_size(sizeof(u32)) +
506 nla_total_size(sizeof(struct taskstats)) + nla_total_size(0);
507 #ifdef TASKSTATS_NEEDS_PADDING
508 size += nla_total_size(0); /* Padding for alignment */
509 #endif
510 return size;
511 }
512
cmd_attr_pid(struct genl_info * info)513 static int cmd_attr_pid(struct genl_info *info)
514 {
515 struct taskstats *stats;
516 struct sk_buff *rep_skb;
517 size_t size;
518 u32 pid;
519 int rc;
520
521 size = taskstats_packet_size();
522
523 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
524 if (rc < 0)
525 return rc;
526
527 rc = -EINVAL;
528 pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
529 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);
530 if (!stats)
531 goto err;
532
533 rc = fill_stats_for_pid(pid, stats);
534 if (rc < 0)
535 goto err;
536 return send_reply(rep_skb, info);
537 err:
538 nlmsg_free(rep_skb);
539 return rc;
540 }
541
cmd_attr_tgid(struct genl_info * info)542 static int cmd_attr_tgid(struct genl_info *info)
543 {
544 struct taskstats *stats;
545 struct sk_buff *rep_skb;
546 size_t size;
547 u32 tgid;
548 int rc;
549
550 size = taskstats_packet_size();
551
552 rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
553 if (rc < 0)
554 return rc;
555
556 rc = -EINVAL;
557 tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
558 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);
559 if (!stats)
560 goto err;
561
562 rc = fill_stats_for_tgid(tgid, stats);
563 if (rc < 0)
564 goto err;
565 return send_reply(rep_skb, info);
566 err:
567 nlmsg_free(rep_skb);
568 return rc;
569 }
570
taskstats_user_cmd(struct sk_buff * skb,struct genl_info * info)571 static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
572 {
573 if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK])
574 return cmd_attr_register_cpumask(info);
575 else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK])
576 return cmd_attr_deregister_cpumask(info);
577 else if (info->attrs[TASKSTATS_CMD_ATTR_PID])
578 return cmd_attr_pid(info);
579 else if (info->attrs[TASKSTATS_CMD_ATTR_TGID])
580 return cmd_attr_tgid(info);
581 else
582 return -EINVAL;
583 }
584
taskstats_tgid_alloc(struct task_struct * tsk)585 static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk)
586 {
587 struct signal_struct *sig = tsk->signal;
588 struct taskstats *stats;
589
590 if (sig->stats || thread_group_empty(tsk))
591 goto ret;
592
593 /* No problem if kmem_cache_zalloc() fails */
594 stats = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
595
596 spin_lock_irq(&tsk->sighand->siglock);
597 if (!sig->stats) {
598 sig->stats = stats;
599 stats = NULL;
600 }
601 spin_unlock_irq(&tsk->sighand->siglock);
602
603 if (stats)
604 kmem_cache_free(taskstats_cache, stats);
605 ret:
606 return sig->stats;
607 }
608
609 /* Send pid data out on exit */
taskstats_exit(struct task_struct * tsk,int group_dead)610 void taskstats_exit(struct task_struct *tsk, int group_dead)
611 {
612 int rc;
613 struct listener_list *listeners;
614 struct taskstats *stats;
615 struct sk_buff *rep_skb;
616 size_t size;
617 int is_thread_group;
618
619 if (!family_registered)
620 return;
621
622 /*
623 * Size includes space for nested attributes
624 */
625 size = taskstats_packet_size();
626
627 is_thread_group = !!taskstats_tgid_alloc(tsk);
628 if (is_thread_group) {
629 /* PID + STATS + TGID + STATS */
630 size = 2 * size;
631 /* fill the tsk->signal->stats structure */
632 fill_tgid_exit(tsk);
633 }
634
635 listeners = __this_cpu_ptr(&listener_array);
636 if (list_empty(&listeners->list))
637 return;
638
639 rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
640 if (rc < 0)
641 return;
642
643 stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID,
644 task_pid_nr_ns(tsk, &init_pid_ns));
645 if (!stats)
646 goto err;
647
648 fill_stats(&init_user_ns, &init_pid_ns, tsk, stats);
649
650 /*
651 * Doesn't matter if tsk is the leader or the last group member leaving
652 */
653 if (!is_thread_group || !group_dead)
654 goto send;
655
656 stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID,
657 task_tgid_nr_ns(tsk, &init_pid_ns));
658 if (!stats)
659 goto err;
660
661 memcpy(stats, tsk->signal->stats, sizeof(*stats));
662
663 send:
664 send_cpu_listeners(rep_skb, listeners);
665 return;
666 err:
667 nlmsg_free(rep_skb);
668 }
669
670 static struct genl_ops taskstats_ops = {
671 .cmd = TASKSTATS_CMD_GET,
672 .doit = taskstats_user_cmd,
673 .policy = taskstats_cmd_get_policy,
674 .flags = GENL_ADMIN_PERM,
675 };
676
677 static struct genl_ops cgroupstats_ops = {
678 .cmd = CGROUPSTATS_CMD_GET,
679 .doit = cgroupstats_user_cmd,
680 .policy = cgroupstats_cmd_get_policy,
681 };
682
683 /* Needed early in initialization */
taskstats_init_early(void)684 void __init taskstats_init_early(void)
685 {
686 unsigned int i;
687
688 taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC);
689 for_each_possible_cpu(i) {
690 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
691 init_rwsem(&(per_cpu(listener_array, i).sem));
692 }
693 }
694
taskstats_init(void)695 static int __init taskstats_init(void)
696 {
697 int rc;
698
699 rc = genl_register_family(&family);
700 if (rc)
701 return rc;
702
703 rc = genl_register_ops(&family, &taskstats_ops);
704 if (rc < 0)
705 goto err;
706
707 rc = genl_register_ops(&family, &cgroupstats_ops);
708 if (rc < 0)
709 goto err_cgroup_ops;
710
711 family_registered = 1;
712 pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
713 return 0;
714 err_cgroup_ops:
715 genl_unregister_ops(&family, &taskstats_ops);
716 err:
717 genl_unregister_family(&family);
718 return rc;
719 }
720
721 /*
722 * late initcall ensures initialization of statistics collection
723 * mechanisms precedes initialization of the taskstats interface
724 */
725 late_initcall(taskstats_init);
726