kernel/taskstats.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * taskstats.c - Export per-task statistics to userland
   4  *
   5  * Copyright (C) Shailabh Nagar, IBM Corp. 2006
   6  *           (C) Balbir Singh,   IBM Corp. 2006
   7  */
   8
   9 #include <linux/kernel.h>
  10 #include <linux/taskstats_kern.h>
  11 #include <linux/tsacct_kern.h>
  12 #include <linux/acct.h>
  13 #include <linux/delayacct.h>
  14 #include <linux/cpumask.h>
  15 #include <linux/percpu.h>
  16 #include <linux/slab.h>
  17 #include <linux/cgroupstats.h>
  18 #include <linux/cgroup.h>
  19 #include <linux/fs.h>
  20 #include <linux/file.h>
  21 #include <linux/pid_namespace.h>
  22 #include <net/genetlink.h>
  23 #include <linux/atomic.h>
  24 #include <linux/sched/cputime.h>
  25
  26 /*
  27  * Maximum length of a cpumask that can be specified in
  28  * the TASKSTATS_CMD_ATTR_REGISTER/DEREGISTER_CPUMASK attribute
  29  */
  30 #define TASKSTATS_CPUMASK_MAXLEN        (100+6*NR_CPUS)
  31
  32 static DEFINE_PER_CPU(__u32, taskstats_seqnum);
  33 static int family_registered;
  34 struct kmem_cache *taskstats_cache;
  35
  36 static struct genl_family family;
  37
  38 static const struct nla_policy taskstats_cmd_get_policy[] = {
  39         [TASKSTATS_CMD_ATTR_PID]  = { .type = NLA_U32 },
  40         [TASKSTATS_CMD_ATTR_TGID] = { .type = NLA_U32 },
  41         [TASKSTATS_CMD_ATTR_REGISTER_CPUMASK] = { .type = NLA_STRING },
  42         [TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK] = { .type = NLA_STRING },};
  43
  44 static const struct nla_policy cgroupstats_cmd_get_policy[] = {
  45         [CGROUPSTATS_CMD_ATTR_FD] = { .type = NLA_U32 },
  46 };
  47
  48 struct listener {
  49         struct list_head list;
  50         pid_t pid;
  51         char valid;
  52 };
  53
  54 struct listener_list {
  55         struct rw_semaphore sem;
  56         struct list_head list;
  57 };
  58 static DEFINE_PER_CPU(struct listener_list, listener_array);
  59
  60 enum actions {
  61         REGISTER,
  62         DEREGISTER,
  63         CPU_DONT_CARE
  64 };
  65
  66 static int prepare_reply(struct genl_info *info, u8 cmd, struct sk_buff **skbp,
  67                                 size_t size)
  68 {
  69         struct sk_buff *skb;
  70         void *reply;
  71
  72         /*
  73          * If new attributes are added, please revisit this allocation
  74          */
  75         skb = genlmsg_new(size, GFP_KERNEL);
  76         if (!skb)
  77                 return -ENOMEM;
  78
  79         if (!info) {
  80                 int seq = this_cpu_inc_return(taskstats_seqnum) - 1;
  81
  82                 reply = genlmsg_put(skb, 0, seq, &family, 0, cmd);
  83         } else
  84                 reply = genlmsg_put_reply(skb, info, &family, 0, cmd);
  85         if (reply == NULL) {
  86                 nlmsg_free(skb);
  87                 return -EINVAL;
  88         }
  89
  90         *skbp = skb;
  91         return 0;
  92 }
  93
  94 /*
  95  * Send taskstats data in @skb to listener with nl_pid @pid
  96  */
  97 static int send_reply(struct sk_buff *skb, struct genl_info *info)
  98 {
  99         struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
 100         void *reply = genlmsg_data(genlhdr);
 101
 102         genlmsg_end(skb, reply);
 103
 104         return genlmsg_reply(skb, info);
 105 }
 106
 107 /*
 108  * Send taskstats data in @skb to listeners registered for @cpu's exit data
 109  */
 110 static void send_cpu_listeners(struct sk_buff *skb,
 111                                         struct listener_list *listeners)
 112 {
 113         struct genlmsghdr *genlhdr = nlmsg_data(nlmsg_hdr(skb));
 114         struct listener *s, *tmp;
 115         struct sk_buff *skb_next, *skb_cur = skb;
 116         void *reply = genlmsg_data(genlhdr);
 117         int delcount = 0;
 118
 119         genlmsg_end(skb, reply);
 120
 121         down_read(&listeners->sem);
 122         list_for_each_entry(s, &listeners->list, list) {
 123                 int rc;
 124
 125                 skb_next = NULL;
 126                 if (!list_is_last(&s->list, &listeners->list)) {
 127                         skb_next = skb_clone(skb_cur, GFP_KERNEL);
 128                         if (!skb_next)
 129                                 break;
 130                 }
 131                 rc = genlmsg_unicast(&init_net, skb_cur, s->pid);
 132                 if (rc == -ECONNREFUSED) {
 133                         s->valid = 0;
 134                         delcount++;
 135                 }
 136                 skb_cur = skb_next;
 137         }
 138         up_read(&listeners->sem);
 139
 140         if (skb_cur)
 141                 nlmsg_free(skb_cur);
 142
 143         if (!delcount)
 144                 return;
 145
 146         /* Delete invalidated entries */
 147         down_write(&listeners->sem);
 148         list_for_each_entry_safe(s, tmp, &listeners->list, list) {
 149                 if (!s->valid) {
 150                         list_del(&s->list);
 151                         kfree(s);
 152                 }
 153         }
 154         up_write(&listeners->sem);
 155 }
 156
 157 static void exe_add_tsk(struct taskstats *stats, struct task_struct *tsk)
 158 {
 159         /* No idea if I'm allowed to access that here, now. */
 160         struct file *exe_file = get_task_exe_file(tsk);
 161
 162         if (exe_file) {
 163                 /* Following cp_new_stat64() in stat.c . */
 164                 stats->ac_exe_dev =
 165                         huge_encode_dev(exe_file->f_inode->i_sb->s_dev);
 166                 stats->ac_exe_inode = exe_file->f_inode->i_ino;
 167                 fput(exe_file);
 168         } else {
 169                 stats->ac_exe_dev = 0;
 170                 stats->ac_exe_inode = 0;
 171         }
 172 }
 173
 174 static void fill_stats(struct user_namespace *user_ns,
 175                        struct pid_namespace *pid_ns,
 176                        struct task_struct *tsk, struct taskstats *stats)
 177 {
 178         memset(stats, 0, sizeof(*stats));
 179         /*
 180          * Each accounting subsystem adds calls to its functions to
 181          * fill in relevant parts of struct taskstsats as follows
 182          *
 183          *      per-task-foo(stats, tsk);
 184          */
 185
 186         delayacct_add_tsk(stats, tsk);
 187
 188         /* fill in basic acct fields */
 189         stats->version = TASKSTATS_VERSION;
 190         stats->nvcsw = tsk->nvcsw;
 191         stats->nivcsw = tsk->nivcsw;
 192         bacct_add_tsk(user_ns, pid_ns, stats, tsk);
 193
 194         /* fill in extended acct fields */
 195         xacct_add_tsk(stats, tsk);
 196
 197         /* add executable info */
 198         exe_add_tsk(stats, tsk);
 199 }
 200
 201 static int fill_stats_for_pid(pid_t pid, struct taskstats *stats)
 202 {
 203         struct task_struct *tsk;
 204
 205         tsk = find_get_task_by_vpid(pid);
 206         if (!tsk)
 207                 return -ESRCH;
 208         fill_stats(current_user_ns(), task_active_pid_ns(current), tsk, stats);
 209         put_task_struct(tsk);
 210         return 0;
 211 }
 212
 213 static int fill_stats_for_tgid(pid_t tgid, struct taskstats *stats)
 214 {
 215         struct task_struct *tsk, *first;
 216         unsigned long flags;
 217         int rc = -ESRCH;
 218         u64 delta, utime, stime;
 219         u64 start_time;
 220
 221         /*
 222          * Add additional stats from live tasks except zombie thread group
 223          * leaders who are already counted with the dead tasks
 224          */
 225         rcu_read_lock();
 226         first = find_task_by_vpid(tgid);
 227
 228         if (!first || !lock_task_sighand(first, &flags))
 229                 goto out;
 230
 231         if (first->signal->stats)
 232                 memcpy(stats, first->signal->stats, sizeof(*stats));
 233         else
 234                 memset(stats, 0, sizeof(*stats));
 235
 236         tsk = first;
 237         start_time = ktime_get_ns();
 238         do {
 239                 if (tsk->exit_state)
 240                         continue;
 241                 /*
 242                  * Accounting subsystem can call its functions here to
 243                  * fill in relevant parts of struct taskstsats as follows
 244                  *
 245                  *      per-task-foo(stats, tsk);
 246                  */
 247                 delayacct_add_tsk(stats, tsk);
 248
 249                 /* calculate task elapsed time in nsec */
 250                 delta = start_time - tsk->start_time;
 251                 /* Convert to micro seconds */
 252                 do_div(delta, NSEC_PER_USEC);
 253                 stats->ac_etime += delta;
 254
 255                 task_cputime(tsk, &utime, &stime);
 256                 stats->ac_utime += div_u64(utime, NSEC_PER_USEC);
 257                 stats->ac_stime += div_u64(stime, NSEC_PER_USEC);
 258
 259                 stats->nvcsw += tsk->nvcsw;
 260                 stats->nivcsw += tsk->nivcsw;
 261         } while_each_thread(first, tsk);
 262
 263         unlock_task_sighand(first, &flags);
 264         rc = 0;
 265 out:
 266         rcu_read_unlock();
 267
 268         stats->version = TASKSTATS_VERSION;
 269         /*
 270          * Accounting subsystems can also add calls here to modify
 271          * fields of taskstats.
 272          */
 273         return rc;
 274 }
 275
 276 static void fill_tgid_exit(struct task_struct *tsk)
 277 {
 278         unsigned long flags;
 279
 280         spin_lock_irqsave(&tsk->sighand->siglock, flags);
 281         if (!tsk->signal->stats)
 282                 goto ret;
 283
 284         /*
 285          * Each accounting subsystem calls its functions here to
 286          * accumalate its per-task stats for tsk, into the per-tgid structure
 287          *
 288          *      per-task-foo(tsk->signal->stats, tsk);
 289          */
 290         delayacct_add_tsk(tsk->signal->stats, tsk);
 291 ret:
 292         spin_unlock_irqrestore(&tsk->sighand->siglock, flags);
 293         return;
 294 }
 295
 296 static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd)
 297 {
 298         struct listener_list *listeners;
 299         struct listener *s, *tmp, *s2;
 300         unsigned int cpu;
 301         int ret = 0;
 302
 303         if (!cpumask_subset(mask, cpu_possible_mask))
 304                 return -EINVAL;
 305
 306         if (current_user_ns() != &init_user_ns)
 307                 return -EINVAL;
 308
 309         if (task_active_pid_ns(current) != &init_pid_ns)
 310                 return -EINVAL;
 311
 312         if (isadd == REGISTER) {
 313                 for_each_cpu(cpu, mask) {
 314                         s = kmalloc_node(sizeof(struct listener),
 315                                         GFP_KERNEL, cpu_to_node(cpu));
 316                         if (!s) {
 317                                 ret = -ENOMEM;
 318                                 goto cleanup;
 319                         }
 320                         s->pid = pid;
 321                         s->valid = 1;
 322
 323                         listeners = &per_cpu(listener_array, cpu);
 324                         down_write(&listeners->sem);
 325                         list_for_each_entry(s2, &listeners->list, list) {
 326                                 if (s2->pid == pid && s2->valid)
 327                                         goto exists;
 328                         }
 329                         list_add(&s->list, &listeners->list);
 330                         s = NULL;
 331 exists:
 332                         up_write(&listeners->sem);
 333                         kfree(s); /* nop if NULL */
 334                 }
 335                 return 0;
 336         }
 337
 338         /* Deregister or cleanup */
 339 cleanup:
 340         for_each_cpu(cpu, mask) {
 341                 listeners = &per_cpu(listener_array, cpu);
 342                 down_write(&listeners->sem);
 343                 list_for_each_entry_safe(s, tmp, &listeners->list, list) {
 344                         if (s->pid == pid) {
 345                                 list_del(&s->list);
 346                                 kfree(s);
 347                                 break;
 348                         }
 349                 }
 350                 up_write(&listeners->sem);
 351         }
 352         return ret;
 353 }
 354
 355 static int parse(struct nlattr *na, struct cpumask *mask)
 356 {
 357         char *data;
 358         int len;
 359         int ret;
 360
 361         if (na == NULL)
 362                 return 1;
 363         len = nla_len(na);
 364         if (len > TASKSTATS_CPUMASK_MAXLEN)
 365                 return -E2BIG;
 366         if (len < 1)
 367                 return -EINVAL;
 368         data = kmalloc(len, GFP_KERNEL);
 369         if (!data)
 370                 return -ENOMEM;
 371         nla_strscpy(data, na, len);
 372         ret = cpulist_parse(data, mask);
 373         kfree(data);
 374         return ret;
 375 }
 376
 377 static struct taskstats *mk_reply(struct sk_buff *skb, int type, u32 pid)
 378 {
 379         struct nlattr *na, *ret;
 380         int aggr;
 381
 382         aggr = (type == TASKSTATS_TYPE_PID)
 383                         ? TASKSTATS_TYPE_AGGR_PID
 384                         : TASKSTATS_TYPE_AGGR_TGID;
 385
 386         na = nla_nest_start_noflag(skb, aggr);
 387         if (!na)
 388                 goto err;
 389
 390         if (nla_put(skb, type, sizeof(pid), &pid) < 0) {
 391                 nla_nest_cancel(skb, na);
 392                 goto err;
 393         }
 394         ret = nla_reserve_64bit(skb, TASKSTATS_TYPE_STATS,
 395                                 sizeof(struct taskstats), TASKSTATS_TYPE_NULL);
 396         if (!ret) {
 397                 nla_nest_cancel(skb, na);
 398                 goto err;
 399         }
 400         nla_nest_end(skb, na);
 401
 402         return nla_data(ret);
 403 err:
 404         return NULL;
 405 }
 406
 407 static int cgroupstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
 408 {
 409         int rc = 0;
 410         struct sk_buff *rep_skb;
 411         struct cgroupstats *stats;
 412         struct nlattr *na;
 413         size_t size;
 414         u32 fd;
 415         struct fd f;
 416
 417         na = info->attrs[CGROUPSTATS_CMD_ATTR_FD];
 418         if (!na)
 419                 return -EINVAL;
 420
 421         fd = nla_get_u32(info->attrs[CGROUPSTATS_CMD_ATTR_FD]);
 422         f = fdget(fd);
 423         if (!f.file)
 424                 return 0;
 425
 426         size = nla_total_size(sizeof(struct cgroupstats));
 427
 428         rc = prepare_reply(info, CGROUPSTATS_CMD_NEW, &rep_skb,
 429                                 size);
 430         if (rc < 0)
 431                 goto err;
 432
 433         na = nla_reserve(rep_skb, CGROUPSTATS_TYPE_CGROUP_STATS,
 434                                 sizeof(struct cgroupstats));
 435         if (na == NULL) {
 436                 nlmsg_free(rep_skb);
 437                 rc = -EMSGSIZE;
 438                 goto err;
 439         }
 440
 441         stats = nla_data(na);
 442         memset(stats, 0, sizeof(*stats));
 443
 444         rc = cgroupstats_build(stats, f.file->f_path.dentry);
 445         if (rc < 0) {
 446                 nlmsg_free(rep_skb);
 447                 goto err;
 448         }
 449
 450         rc = send_reply(rep_skb, info);
 451
 452 err:
 453         fdput(f);
 454         return rc;
 455 }
 456
 457 static int cmd_attr_register_cpumask(struct genl_info *info)
 458 {
 459         cpumask_var_t mask;
 460         int rc;
 461
 462         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
 463                 return -ENOMEM;
 464         rc = parse(info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK], mask);
 465         if (rc < 0)
 466                 goto out;
 467         rc = add_del_listener(info->snd_portid, mask, REGISTER);
 468 out:
 469         free_cpumask_var(mask);
 470         return rc;
 471 }
 472
 473 static int cmd_attr_deregister_cpumask(struct genl_info *info)
 474 {
 475         cpumask_var_t mask;
 476         int rc;
 477
 478         if (!alloc_cpumask_var(&mask, GFP_KERNEL))
 479                 return -ENOMEM;
 480         rc = parse(info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK], mask);
 481         if (rc < 0)
 482                 goto out;
 483         rc = add_del_listener(info->snd_portid, mask, DEREGISTER);
 484 out:
 485         free_cpumask_var(mask);
 486         return rc;
 487 }
 488
 489 static size_t taskstats_packet_size(void)
 490 {
 491         size_t size;
 492
 493         size = nla_total_size(sizeof(u32)) +
 494                 nla_total_size_64bit(sizeof(struct taskstats)) +
 495                 nla_total_size(0);
 496
 497         return size;
 498 }
 499
 500 static int cmd_attr_pid(struct genl_info *info)
 501 {
 502         struct taskstats *stats;
 503         struct sk_buff *rep_skb;
 504         size_t size;
 505         u32 pid;
 506         int rc;
 507
 508         size = taskstats_packet_size();
 509
 510         rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
 511         if (rc < 0)
 512                 return rc;
 513
 514         rc = -EINVAL;
 515         pid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_PID]);
 516         stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID, pid);
 517         if (!stats)
 518                 goto err;
 519
 520         rc = fill_stats_for_pid(pid, stats);
 521         if (rc < 0)
 522                 goto err;
 523         return send_reply(rep_skb, info);
 524 err:
 525         nlmsg_free(rep_skb);
 526         return rc;
 527 }
 528
 529 static int cmd_attr_tgid(struct genl_info *info)
 530 {
 531         struct taskstats *stats;
 532         struct sk_buff *rep_skb;
 533         size_t size;
 534         u32 tgid;
 535         int rc;
 536
 537         size = taskstats_packet_size();
 538
 539         rc = prepare_reply(info, TASKSTATS_CMD_NEW, &rep_skb, size);
 540         if (rc < 0)
 541                 return rc;
 542
 543         rc = -EINVAL;
 544         tgid = nla_get_u32(info->attrs[TASKSTATS_CMD_ATTR_TGID]);
 545         stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID, tgid);
 546         if (!stats)
 547                 goto err;
 548
 549         rc = fill_stats_for_tgid(tgid, stats);
 550         if (rc < 0)
 551                 goto err;
 552         return send_reply(rep_skb, info);
 553 err:
 554         nlmsg_free(rep_skb);
 555         return rc;
 556 }
 557
 558 static int taskstats_user_cmd(struct sk_buff *skb, struct genl_info *info)
 559 {
 560         if (info->attrs[TASKSTATS_CMD_ATTR_REGISTER_CPUMASK])
 561                 return cmd_attr_register_cpumask(info);
 562         else if (info->attrs[TASKSTATS_CMD_ATTR_DEREGISTER_CPUMASK])
 563                 return cmd_attr_deregister_cpumask(info);
 564         else if (info->attrs[TASKSTATS_CMD_ATTR_PID])
 565                 return cmd_attr_pid(info);
 566         else if (info->attrs[TASKSTATS_CMD_ATTR_TGID])
 567                 return cmd_attr_tgid(info);
 568         else
 569                 return -EINVAL;
 570 }
 571
 572 static struct taskstats *taskstats_tgid_alloc(struct task_struct *tsk)
 573 {
 574         struct signal_struct *sig = tsk->signal;
 575         struct taskstats *stats_new, *stats;
 576
 577         /* Pairs with smp_store_release() below. */
 578         stats = smp_load_acquire(&sig->stats);
 579         if (stats || thread_group_empty(tsk))
 580                 return stats;
 581
 582         /* No problem if kmem_cache_zalloc() fails */
 583         stats_new = kmem_cache_zalloc(taskstats_cache, GFP_KERNEL);
 584
 585         spin_lock_irq(&tsk->sighand->siglock);
 586         stats = sig->stats;
 587         if (!stats) {
 588                 /*
 589                  * Pairs with smp_store_release() above and order the
 590                  * kmem_cache_zalloc().
 591                  */
 592                 smp_store_release(&sig->stats, stats_new);
 593                 stats = stats_new;
 594                 stats_new = NULL;
 595         }
 596         spin_unlock_irq(&tsk->sighand->siglock);
 597
 598         if (stats_new)
 599                 kmem_cache_free(taskstats_cache, stats_new);
 600
 601         return stats;
 602 }
 603
 604 /* Send pid data out on exit */
 605 void taskstats_exit(struct task_struct *tsk, int group_dead)
 606 {
 607         int rc;
 608         struct listener_list *listeners;
 609         struct taskstats *stats;
 610         struct sk_buff *rep_skb;
 611         size_t size;
 612         int is_thread_group;
 613
 614         if (!family_registered)
 615                 return;
 616
 617         /*
 618          * Size includes space for nested attributes
 619          */
 620         size = taskstats_packet_size();
 621
 622         is_thread_group = !!taskstats_tgid_alloc(tsk);
 623         if (is_thread_group) {
 624                 /* PID + STATS + TGID + STATS */
 625                 size = 2 * size;
 626                 /* fill the tsk->signal->stats structure */
 627                 fill_tgid_exit(tsk);
 628         }
 629
 630         listeners = raw_cpu_ptr(&listener_array);
 631         if (list_empty(&listeners->list))
 632                 return;
 633
 634         rc = prepare_reply(NULL, TASKSTATS_CMD_NEW, &rep_skb, size);
 635         if (rc < 0)
 636                 return;
 637
 638         stats = mk_reply(rep_skb, TASKSTATS_TYPE_PID,
 639                          task_pid_nr_ns(tsk, &init_pid_ns));
 640         if (!stats)
 641                 goto err;
 642
 643         fill_stats(&init_user_ns, &init_pid_ns, tsk, stats);
 644         if (group_dead)
 645                 stats->ac_flag |= AGROUP;
 646
 647         /*
 648          * Doesn't matter if tsk is the leader or the last group member leaving
 649          */
 650         if (!is_thread_group || !group_dead)
 651                 goto send;
 652
 653         stats = mk_reply(rep_skb, TASKSTATS_TYPE_TGID,
 654                          task_tgid_nr_ns(tsk, &init_pid_ns));
 655         if (!stats)
 656                 goto err;
 657
 658         memcpy(stats, tsk->signal->stats, sizeof(*stats));
 659
 660 send:
 661         send_cpu_listeners(rep_skb, listeners);
 662         return;
 663 err:
 664         nlmsg_free(rep_skb);
 665 }
 666
 667 static const struct genl_ops taskstats_ops[] = {
 668         {
 669                 .cmd            = TASKSTATS_CMD_GET,
 670                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 671                 .doit           = taskstats_user_cmd,
 672                 .policy         = taskstats_cmd_get_policy,
 673                 .maxattr        = ARRAY_SIZE(taskstats_cmd_get_policy) - 1,
 674                 .flags          = GENL_ADMIN_PERM,
 675         },
 676         {
 677                 .cmd            = CGROUPSTATS_CMD_GET,
 678                 .validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,
 679                 .doit           = cgroupstats_user_cmd,
 680                 .policy         = cgroupstats_cmd_get_policy,
 681                 .maxattr        = ARRAY_SIZE(cgroupstats_cmd_get_policy) - 1,
 682         },
 683 };
 684
 685 static struct genl_family family __ro_after_init = {
 686         .name           = TASKSTATS_GENL_NAME,
 687         .version        = TASKSTATS_GENL_VERSION,
 688         .module         = THIS_MODULE,
 689         .ops            = taskstats_ops,
 690         .n_ops          = ARRAY_SIZE(taskstats_ops),
 691         .resv_start_op  = CGROUPSTATS_CMD_GET + 1,
 692         .netnsok        = true,
 693 };
 694
 695 /* Needed early in initialization */
 696 void __init taskstats_init_early(void)
 697 {
 698         unsigned int i;
 699
 700         taskstats_cache = KMEM_CACHE(taskstats, SLAB_PANIC);
 701         for_each_possible_cpu(i) {
 702                 INIT_LIST_HEAD(&(per_cpu(listener_array, i).list));
 703                 init_rwsem(&(per_cpu(listener_array, i).sem));
 704         }
 705 }
 706
 707 static int __init taskstats_init(void)
 708 {
 709         int rc;
 710
 711         rc = genl_register_family(&family);
 712         if (rc)
 713                 return rc;
 714
 715         family_registered = 1;
 716         pr_info("registered taskstats version %d\n", TASKSTATS_GENL_VERSION);
 717         return 0;
 718 }
 719
 720 /*
 721  * late initcall ensures initialization of statistics collection
 722  * mechanisms precedes initialization of the taskstats interface
 723  */
 724 late_initcall(taskstats_init);