src/lttng-statedump-impl.c

   1 /* SPDX-License-Identifier: (GPL-2.0-only or LGPL-2.1-only)
   2  *
   3  * lttng-statedump.c
   4  *
   5  * Linux Trace Toolkit Next Generation Kernel State Dump
   6  *
   7  * Copyright 2005 Jean-Hugues Deschenes <jean-hugues.deschenes@polymtl.ca>
   8  * Copyright 2006-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   9  *
  10  * Changes:
  11  *      Eric Clement:                   Add listing of network IP interface
  12  *      2006, 2007 Mathieu Desnoyers    Fix kernel threads
  13  *                                      Various updates
  14  */
  15
  16 #include <linux/init.h>
  17 #include <linux/module.h>
  18 #include <linux/netlink.h>
  19 #include <linux/inet.h>
  20 #include <linux/ip.h>
  21 #include <linux/kthread.h>
  22 #include <linux/proc_fs.h>
  23 #include <linux/file.h>
  24 #include <linux/interrupt.h>
  25 #include <linux/irqnr.h>
  26 #include <linux/cpu.h>
  27 #include <linux/netdevice.h>
  28 #include <linux/inetdevice.h>
  29 #include <linux/sched.h>
  30 #include <linux/mm.h>
  31 #include <linux/swap.h>
  32 #include <linux/wait.h>
  33 #include <linux/mutex.h>
  34 #include <linux/device.h>
  35
  36 #include <lttng/events.h>
  37 #include <lttng/tracer.h>
  38 #include <wrapper/irqdesc.h>
  39 #include <wrapper/fdtable.h>
  40 #include <wrapper/namespace.h>
  41 #include <wrapper/irq.h>
  42 #include <wrapper/tracepoint.h>
  43 #include <wrapper/genhd.h>
  44 #include <wrapper/file.h>
  45 #include <wrapper/fdtable.h>
  46
  47 #ifdef CONFIG_LTTNG_HAS_LIST_IRQ
  48 #include <linux/irq.h>
  49 #endif
  50
  51 /* Define the tracepoints, but do not build the probes */
  52 #define CREATE_TRACE_POINTS
  53 #define TRACE_INCLUDE_PATH instrumentation/events
  54 #define TRACE_INCLUDE_FILE lttng-statedump
  55 #define LTTNG_INSTRUMENTATION
  56 #include <instrumentation/events/lttng-statedump.h>
  57
  58 LTTNG_DEFINE_TRACE(lttng_statedump_block_device,
  59         TP_PROTO(struct lttng_kernel_session *session,
  60                 dev_t dev, const char *diskname),
  61         TP_ARGS(session, dev, diskname));
  62
  63 LTTNG_DEFINE_TRACE(lttng_statedump_end,
  64         TP_PROTO(struct lttng_kernel_session *session),
  65         TP_ARGS(session));
  66
  67 LTTNG_DEFINE_TRACE(lttng_statedump_interrupt,
  68         TP_PROTO(struct lttng_kernel_session *session,
  69                 unsigned int irq, const char *chip_name,
  70                 struct irqaction *action),
  71         TP_ARGS(session, irq, chip_name, action));
  72
  73 LTTNG_DEFINE_TRACE(lttng_statedump_file_descriptor,
  74         TP_PROTO(struct lttng_kernel_session *session,
  75                 struct files_struct *files,
  76                 int fd, const char *filename,
  77                 unsigned int flags, fmode_t fmode),
  78         TP_ARGS(session, files, fd, filename, flags, fmode));
  79
  80 LTTNG_DEFINE_TRACE(lttng_statedump_start,
  81         TP_PROTO(struct lttng_kernel_session *session),
  82         TP_ARGS(session));
  83
  84 LTTNG_DEFINE_TRACE(lttng_statedump_process_state,
  85         TP_PROTO(struct lttng_kernel_session *session,
  86                 struct task_struct *p,
  87                 int type, int mode, int submode, int status,
  88                 struct files_struct *files),
  89         TP_ARGS(session, p, type, mode, submode, status, files));
  90
  91 LTTNG_DEFINE_TRACE(lttng_statedump_process_pid_ns,
  92         TP_PROTO(struct lttng_kernel_session *session,
  93                 struct task_struct *p,
  94                 struct pid_namespace *pid_ns),
  95         TP_ARGS(session, p, pid_ns));
  96
  97 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,6,0))
  98 LTTNG_DEFINE_TRACE(lttng_statedump_process_cgroup_ns,
  99         TP_PROTO(struct lttng_kernel_session *session,
 100                 struct task_struct *p,
 101                 struct cgroup_namespace *cgroup_ns),
 102         TP_ARGS(session, p, cgroup_ns));
 103 #endif
 104
 105 LTTNG_DEFINE_TRACE(lttng_statedump_process_ipc_ns,
 106         TP_PROTO(struct lttng_kernel_session *session,
 107                 struct task_struct *p,
 108                 struct ipc_namespace *ipc_ns),
 109         TP_ARGS(session, p, ipc_ns));
 110
 111 #ifndef LTTNG_MNT_NS_MISSING_HEADER
 112 LTTNG_DEFINE_TRACE(lttng_statedump_process_mnt_ns,
 113         TP_PROTO(struct lttng_kernel_session *session,
 114                 struct task_struct *p,
 115                 struct mnt_namespace *mnt_ns),
 116         TP_ARGS(session, p, mnt_ns));
 117 #endif
 118
 119 LTTNG_DEFINE_TRACE(lttng_statedump_process_net_ns,
 120         TP_PROTO(struct lttng_kernel_session *session,
 121                 struct task_struct *p,
 122                 struct net *net_ns),
 123         TP_ARGS(session, p, net_ns));
 124
 125 LTTNG_DEFINE_TRACE(lttng_statedump_process_user_ns,
 126         TP_PROTO(struct lttng_kernel_session *session,
 127                 struct task_struct *p,
 128                 struct user_namespace *user_ns),
 129         TP_ARGS(session, p, user_ns));
 130
 131 LTTNG_DEFINE_TRACE(lttng_statedump_process_uts_ns,
 132         TP_PROTO(struct lttng_kernel_session *session,
 133                 struct task_struct *p,
 134                 struct uts_namespace *uts_ns),
 135         TP_ARGS(session, p, uts_ns));
 136
 137 LTTNG_DEFINE_TRACE(lttng_statedump_process_time_ns,
 138         TP_PROTO(struct lttng_kernel_session *session,
 139                 struct task_struct *p,
 140                 struct time_namespace *time_ns),
 141         TP_ARGS(session, p, time_ns));
 142
 143 LTTNG_DEFINE_TRACE(lttng_statedump_network_interface,
 144         TP_PROTO(struct lttng_kernel_session *session,
 145                 struct net_device *dev, struct in_ifaddr *ifa),
 146         TP_ARGS(session, dev, ifa));
 147
 148 #ifdef LTTNG_HAVE_STATEDUMP_CPU_TOPOLOGY
 149 LTTNG_DEFINE_TRACE(lttng_statedump_cpu_topology,
 150         TP_PROTO(struct lttng_kernel_session *session, struct cpuinfo_x86 *c),
 151         TP_ARGS(session, c));
 152 #endif
 153
 154 struct lttng_fd_ctx {
 155         char *page;
 156         struct lttng_kernel_session *session;
 157         struct files_struct *files;
 158 };
 159
 160 /*
 161  * Protected by the trace lock.
 162  */
 163 static struct delayed_work cpu_work[NR_CPUS];
 164 static DECLARE_WAIT_QUEUE_HEAD(statedump_wq);
 165 static atomic_t kernel_threads_to_run;
 166
 167 enum lttng_thread_type {
 168         LTTNG_USER_THREAD = 0,
 169         LTTNG_KERNEL_THREAD = 1,
 170 };
 171
 172 enum lttng_execution_mode {
 173         LTTNG_USER_MODE = 0,
 174         LTTNG_SYSCALL = 1,
 175         LTTNG_TRAP = 2,
 176         LTTNG_IRQ = 3,
 177         LTTNG_SOFTIRQ = 4,
 178         LTTNG_MODE_UNKNOWN = 5,
 179 };
 180
 181 enum lttng_execution_submode {
 182         LTTNG_NONE = 0,
 183         LTTNG_UNKNOWN = 1,
 184 };
 185
 186 enum lttng_process_status {
 187         LTTNG_UNNAMED = 0,
 188         LTTNG_WAIT_FORK = 1,
 189         LTTNG_WAIT_CPU = 2,
 190         LTTNG_EXIT = 3,
 191         LTTNG_ZOMBIE = 4,
 192         LTTNG_WAIT = 5,
 193         LTTNG_RUN = 6,
 194         LTTNG_DEAD = 7,
 195 };
 196
 197
 198 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,11,0))
 199
 200 #define LTTNG_PART_STRUCT_TYPE struct block_device
 201
 202 static
 203 int lttng_get_part_name(struct gendisk *disk, struct block_device *part, char *name_buf)
 204 {
 205         const char *p;
 206
 207         p = bdevname(part, name_buf);
 208         if (!p)
 209                 return -ENOSYS;
 210
 211         return 0;
 212 }
 213
 214 static
 215 dev_t lttng_get_part_devt(struct block_device *part)
 216 {
 217         return part->bd_dev;
 218 }
 219
 220 #else
 221
 222 #define LTTNG_PART_STRUCT_TYPE struct hd_struct
 223
 224 static
 225 int lttng_get_part_name(struct gendisk *disk, struct hd_struct *part, char *name_buf)
 226 {
 227         const char *p;
 228         struct block_device bdev;
 229
 230         /*
 231          * Create a partial 'struct blockdevice' to use
 232          * 'bdevname()' which is a simple wrapper over
 233          * 'disk_name()' but has the honor to be EXPORT_SYMBOL.
 234          */
 235         bdev.bd_disk = disk;
 236         bdev.bd_part = part;
 237
 238         p = bdevname(&bdev, name_buf);
 239         if (!p)
 240                 return -ENOSYS;
 241
 242         return 0;
 243 }
 244
 245 static
 246 dev_t lttng_get_part_devt(struct hd_struct *part)
 247 {
 248         return part_devt(part);
 249 }
 250 #endif
 251
 252 static
 253 int lttng_enumerate_block_devices(struct lttng_kernel_session *session)
 254 {
 255         struct class *ptr_block_class;
 256         struct device_type *ptr_disk_type;
 257         struct class_dev_iter iter;
 258         struct device *dev;
 259         int ret = 0;
 260
 261         ptr_block_class = wrapper_get_block_class();
 262         if (!ptr_block_class) {
 263                 ret = -ENOSYS;
 264                 goto end;
 265         }
 266         ptr_disk_type = wrapper_get_disk_type();
 267         if (!ptr_disk_type) {
 268                 ret = -ENOSYS;
 269                 goto end;
 270         }
 271         class_dev_iter_init(&iter, ptr_block_class, NULL, ptr_disk_type);
 272         while ((dev = class_dev_iter_next(&iter))) {
 273                 struct disk_part_iter piter;
 274                 struct gendisk *disk = dev_to_disk(dev);
 275                 LTTNG_PART_STRUCT_TYPE *part;
 276
 277                 /*
 278                  * Don't show empty devices or things that have been
 279                  * suppressed
 280                  */
 281                 if (get_capacity(disk) == 0 ||
 282                     (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
 283                         continue;
 284
 285                 /*
 286                  * The original 'disk_part_iter_init' returns void, but our
 287                  * wrapper can fail to lookup the original symbol.
 288                  */
 289                 if (wrapper_disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0) < 0) {
 290                         ret = -ENOSYS;
 291                         goto iter_exit;
 292                 }
 293
 294                 while ((part = wrapper_disk_part_iter_next(&piter))) {
 295                         char name_buf[BDEVNAME_SIZE];
 296
 297                         if (lttng_get_part_name(disk, part, name_buf) == -ENOSYS) {
 298                                 wrapper_disk_part_iter_exit(&piter);
 299                                 ret = -ENOSYS;
 300                                 goto iter_exit;
 301                         }
 302                         trace_lttng_statedump_block_device(session,
 303                                         lttng_get_part_devt(part), name_buf);
 304                 }
 305                 wrapper_disk_part_iter_exit(&piter);
 306         }
 307 iter_exit:
 308         class_dev_iter_exit(&iter);
 309 end:
 310         return ret;
 311 }
 312
 313 #ifdef CONFIG_INET
 314
 315 static
 316 void lttng_enumerate_device(struct lttng_kernel_session *session,
 317                 struct net_device *dev)
 318 {
 319         struct in_device *in_dev;
 320         struct in_ifaddr *ifa;
 321
 322         if (dev->flags & IFF_UP) {
 323                 in_dev = in_dev_get(dev);
 324                 if (in_dev) {
 325                         for (ifa = in_dev->ifa_list; ifa != NULL;
 326                              ifa = ifa->ifa_next) {
 327                                 trace_lttng_statedump_network_interface(
 328                                         session, dev, ifa);
 329                         }
 330                         in_dev_put(in_dev);
 331                 }
 332         } else {
 333                 trace_lttng_statedump_network_interface(
 334                         session, dev, NULL);
 335         }
 336 }
 337
 338 static
 339 int lttng_enumerate_network_ip_interface(struct lttng_kernel_session *session)
 340 {
 341         struct net_device *dev;
 342
 343         read_lock(&dev_base_lock);
 344         for_each_netdev(&init_net, dev)
 345                 lttng_enumerate_device(session, dev);
 346         read_unlock(&dev_base_lock);
 347
 348         return 0;
 349 }
 350 #else /* CONFIG_INET */
 351 static inline
 352 int lttng_enumerate_network_ip_interface(struct lttng_kernel_session *session)
 353 {
 354         return 0;
 355 }
 356 #endif /* CONFIG_INET */
 357
 358 static
 359 int lttng_dump_one_fd(const void *p, struct file *file, unsigned int fd)
 360 {
 361         const struct lttng_fd_ctx *ctx = p;
 362         const char *s = d_path(&file->f_path, ctx->page, PAGE_SIZE);
 363         unsigned int flags = file->f_flags;
 364         struct fdtable *fdt;
 365
 366         /*
 367          * We don't expose kernel internal flags, only userspace-visible
 368          * flags.
 369          */
 370         flags &= ~FMODE_NONOTIFY;
 371         fdt = files_fdtable(ctx->files);
 372         /*
 373          * We need to check here again whether fd is within the fdt
 374          * max_fds range, because we might be seeing a different
 375          * files_fdtable() than iterate_fd(), assuming only RCU is
 376          * protecting the read. In reality, iterate_fd() holds
 377          * file_lock, which should ensure the fdt does not change while
 378          * the lock is taken, but we are not aware whether this is
 379          * guaranteed or not, so play safe.
 380          */
 381         if (fd < fdt->max_fds && lttng_close_on_exec(fd, fdt))
 382                 flags |= O_CLOEXEC;
 383         if (IS_ERR(s)) {
 384                 struct dentry *dentry = file->f_path.dentry;
 385
 386                 /* Make sure we give at least some info */
 387                 spin_lock(&dentry->d_lock);
 388                 trace_lttng_statedump_file_descriptor(ctx->session,
 389                         ctx->files, fd, dentry->d_name.name, flags,
 390                         file->f_mode);
 391                 spin_unlock(&dentry->d_lock);
 392                 goto end;
 393         }
 394         trace_lttng_statedump_file_descriptor(ctx->session,
 395                 ctx->files, fd, s, flags, file->f_mode);
 396 end:
 397         return 0;
 398 }
 399
 400 /* Called with task lock held. */
 401 static
 402 void lttng_enumerate_files(struct lttng_kernel_session *session,
 403                 struct files_struct *files,
 404                 char *tmp)
 405 {
 406         struct lttng_fd_ctx ctx = { .page = tmp, .session = session, .files = files, };
 407
 408         lttng_iterate_fd(files, 0, lttng_dump_one_fd, &ctx);
 409 }
 410
 411 #ifdef LTTNG_HAVE_STATEDUMP_CPU_TOPOLOGY
 412 static
 413 int lttng_enumerate_cpu_topology(struct lttng_kernel_session *session)
 414 {
 415         int cpu;
 416         const cpumask_t *cpumask = cpu_possible_mask;
 417
 418         for (cpu = cpumask_first(cpumask); cpu < nr_cpu_ids;
 419                         cpu = cpumask_next(cpu, cpumask)) {
 420                 trace_lttng_statedump_cpu_topology(session, &cpu_data(cpu));
 421         }
 422
 423         return 0;
 424 }
 425 #else
 426 static
 427 int lttng_enumerate_cpu_topology(struct lttng_kernel_session *session)
 428 {
 429         return 0;
 430 }
 431 #endif
 432
 433 #if 0
 434 /*
 435  * FIXME: we cannot take a mmap_sem while in a RCU read-side critical section
 436  * (scheduling in atomic). Normally, the tasklist lock protects this kind of
 437  * iteration, but it is not exported to modules.
 438  */
 439 static
 440 void lttng_enumerate_task_vm_maps(struct lttng_kernel_session *session,
 441                 struct task_struct *p)
 442 {
 443         struct mm_struct *mm;
 444         struct vm_area_struct *map;
 445         unsigned long ino;
 446
 447         /* get_task_mm does a task_lock... */
 448         mm = get_task_mm(p);
 449         if (!mm)
 450                 return;
 451
 452         map = mm->mmap;
 453         if (map) {
 454                 down_read(&mm->mmap_sem);
 455                 while (map) {
 456                         if (map->vm_file)
 457                                 ino = map->vm_file->lttng_f_dentry->d_inode->i_ino;
 458                         else
 459                                 ino = 0;
 460                         trace_lttng_statedump_vm_map(session, p, map, ino);
 461                         map = map->vm_next;
 462                 }
 463                 up_read(&mm->mmap_sem);
 464         }
 465         mmput(mm);
 466 }
 467
 468 static
 469 int lttng_enumerate_vm_maps(struct lttng_kernel_session *session)
 470 {
 471         struct task_struct *p;
 472
 473         rcu_read_lock();
 474         for_each_process(p)
 475                 lttng_enumerate_task_vm_maps(session, p);
 476         rcu_read_unlock();
 477         return 0;
 478 }
 479 #endif
 480
 481 #ifdef CONFIG_LTTNG_HAS_LIST_IRQ
 482
 483 static
 484 int lttng_list_interrupts(struct lttng_kernel_session *session)
 485 {
 486         unsigned int irq;
 487         unsigned long flags = 0;
 488         struct irq_desc *desc;
 489
 490 #define irq_to_desc     wrapper_irq_to_desc
 491         /* needs irq_desc */
 492         for_each_irq_desc(irq, desc) {
 493                 struct irqaction *action;
 494                 const char *irq_chip_name =
 495                         irq_desc_get_chip(desc)->name ? : "unnamed_irq_chip";
 496
 497                 local_irq_save(flags);
 498                 raw_spin_lock(&desc->lock);
 499                 for (action = desc->action; action; action = action->next) {
 500                         trace_lttng_statedump_interrupt(session,
 501                                 irq, irq_chip_name, action);
 502                 }
 503                 raw_spin_unlock(&desc->lock);
 504                 local_irq_restore(flags);
 505         }
 506         return 0;
 507 #undef irq_to_desc
 508 }
 509 #else
 510 static inline
 511 int lttng_list_interrupts(struct lttng_kernel_session *session)
 512 {
 513         return 0;
 514 }
 515 #endif
 516
 517 /*
 518  * Statedump the task's namespaces using the proc filesystem inode number as
 519  * the unique identifier. The user and pid ns are nested and will be dumped
 520  * recursively.
 521  *
 522  * Called with task lock held.
 523  */
 524 static
 525 void lttng_statedump_process_ns(struct lttng_kernel_session *session,
 526                 struct task_struct *p,
 527                 enum lttng_thread_type type,
 528                 enum lttng_execution_mode mode,
 529                 enum lttng_execution_submode submode,
 530                 enum lttng_process_status status)
 531 {
 532         struct nsproxy *proxy;
 533         struct pid_namespace *pid_ns;
 534         struct user_namespace *user_ns;
 535
 536         /*
 537          * The pid and user namespaces are special, they are nested and
 538          * accessed with specific functions instead of the nsproxy struct
 539          * like the other namespaces.
 540          */
 541         pid_ns = task_active_pid_ns(p);
 542         do {
 543                 trace_lttng_statedump_process_pid_ns(session, p, pid_ns);
 544                 pid_ns = pid_ns ? pid_ns->parent : NULL;
 545         } while (pid_ns);
 546
 547
 548         user_ns = task_cred_xxx(p, user_ns);
 549         do {
 550                 trace_lttng_statedump_process_user_ns(session, p, user_ns);
 551                 /*
 552                  * trace_lttng_statedump_process_user_ns() internally
 553                  * checks whether user_ns is NULL. While this does not
 554                  * appear to be a possible return value for
 555                  * task_cred_xxx(), err on the safe side and check
 556                  * for NULL here as well to be consistent with the
 557                  * paranoid behavior of
 558                  * trace_lttng_statedump_process_user_ns().
 559                  */
 560                 user_ns = user_ns ? user_ns->lttng_user_ns_parent : NULL;
 561         } while (user_ns);
 562
 563         /*
 564          * Back and forth on locking strategy within Linux upstream for nsproxy.
 565          * See Linux upstream commit 728dba3a39c66b3d8ac889ddbe38b5b1c264aec3
 566          * "namespaces: Use task_lock and not rcu to protect nsproxy"
 567          * for details.
 568          */
 569 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,17,0) || \
 570                 LTTNG_UBUNTU_KERNEL_RANGE(3,13,11,36, 3,14,0,0) || \
 571                 LTTNG_UBUNTU_KERNEL_RANGE(3,16,1,11, 3,17,0,0) || \
 572                 LTTNG_RHEL_KERNEL_RANGE(3,10,0,229,13,0, 3,11,0,0,0,0))
 573         proxy = p->nsproxy;
 574 #else
 575         rcu_read_lock();
 576         proxy = task_nsproxy(p);
 577 #endif
 578         if (proxy) {
 579 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,6,0))
 580                 trace_lttng_statedump_process_cgroup_ns(session, p, proxy->cgroup_ns);
 581 #endif
 582                 trace_lttng_statedump_process_ipc_ns(session, p, proxy->ipc_ns);
 583 #ifndef LTTNG_MNT_NS_MISSING_HEADER
 584                 trace_lttng_statedump_process_mnt_ns(session, p, proxy->mnt_ns);
 585 #endif
 586                 trace_lttng_statedump_process_net_ns(session, p, proxy->net_ns);
 587                 trace_lttng_statedump_process_uts_ns(session, p, proxy->uts_ns);
 588 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,6,0))
 589                 trace_lttng_statedump_process_time_ns(session, p, proxy->time_ns);
 590 #endif
 591         }
 592 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,17,0) || \
 593                 LTTNG_UBUNTU_KERNEL_RANGE(3,13,11,36, 3,14,0,0) || \
 594                 LTTNG_UBUNTU_KERNEL_RANGE(3,16,1,11, 3,17,0,0) || \
 595                 LTTNG_RHEL_KERNEL_RANGE(3,10,0,229,13,0, 3,11,0,0,0,0))
 596         /* (nothing) */
 597 #else
 598         rcu_read_unlock();
 599 #endif
 600 }
 601
 602 static
 603 int lttng_enumerate_process_states(struct lttng_kernel_session *session)
 604 {
 605         struct task_struct *g, *p;
 606         char *tmp;
 607
 608         tmp = (char *) __get_free_page(GFP_KERNEL);
 609         if (!tmp)
 610                 return -ENOMEM;
 611
 612         rcu_read_lock();
 613         for_each_process(g) {
 614                 struct files_struct *prev_files = NULL;
 615
 616                 p = g;
 617                 do {
 618                         enum lttng_execution_mode mode =
 619                                 LTTNG_MODE_UNKNOWN;
 620                         enum lttng_execution_submode submode =
 621                                 LTTNG_UNKNOWN;
 622                         enum lttng_process_status status;
 623                         enum lttng_thread_type type;
 624                         struct files_struct *files;
 625
 626                         task_lock(p);
 627                         if (p->exit_state == EXIT_ZOMBIE)
 628                                 status = LTTNG_ZOMBIE;
 629                         else if (p->exit_state == EXIT_DEAD)
 630                                 status = LTTNG_DEAD;
 631                         else if (p->state == TASK_RUNNING) {
 632                                 /* Is this a forked child that has not run yet? */
 633                                 if (list_empty(&p->rt.run_list))
 634                                         status = LTTNG_WAIT_FORK;
 635                                 else
 636                                         /*
 637                                          * All tasks are considered as wait_cpu;
 638                                          * the viewer will sort out if the task
 639                                          * was really running at this time.
 640                                          */
 641                                         status = LTTNG_WAIT_CPU;
 642                         } else if (p->state &
 643                                 (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)) {
 644                                 /* Task is waiting for something to complete */
 645                                 status = LTTNG_WAIT;
 646                         } else
 647                                 status = LTTNG_UNNAMED;
 648                         submode = LTTNG_NONE;
 649
 650                         /*
 651                          * Verification of t->mm is to filter out kernel
 652                          * threads; Viewer will further filter out if a
 653                          * user-space thread was in syscall mode or not.
 654                          */
 655                         if (p->mm)
 656                                 type = LTTNG_USER_THREAD;
 657                         else
 658                                 type = LTTNG_KERNEL_THREAD;
 659                         files = p->files;
 660
 661                         trace_lttng_statedump_process_state(session,
 662                                 p, type, mode, submode, status, files);
 663                         lttng_statedump_process_ns(session,
 664                                 p, type, mode, submode, status);
 665                         /*
 666                          * As an optimisation for the common case, do not
 667                          * repeat information for the same files_struct in
 668                          * two consecutive threads. This is the common case
 669                          * for threads sharing the same fd table. RCU guarantees
 670                          * that the same files_struct pointer is not re-used
 671                          * throughout processes/threads iteration.
 672                          */
 673                         if (files && files != prev_files) {
 674                                 lttng_enumerate_files(session, files, tmp);
 675                                 prev_files = files;
 676                         }
 677                         task_unlock(p);
 678                 } while_each_thread(g, p);
 679         }
 680         rcu_read_unlock();
 681
 682         free_page((unsigned long) tmp);
 683
 684         return 0;
 685 }
 686
 687 static
 688 void lttng_statedump_work_func(struct work_struct *work)
 689 {
 690         if (atomic_dec_and_test(&kernel_threads_to_run))
 691                 /* If we are the last thread, wake up do_lttng_statedump */
 692                 wake_up(&statedump_wq);
 693 }
 694
 695 static
 696 int do_lttng_statedump(struct lttng_kernel_session *session)
 697 {
 698         int cpu, ret;
 699
 700         trace_lttng_statedump_start(session);
 701         ret = lttng_enumerate_process_states(session);
 702         if (ret)
 703                 return ret;
 704         /*
 705          * FIXME
 706          * ret = lttng_enumerate_vm_maps(session);
 707          * if (ret)
 708          *      return ret;
 709          */
 710         ret = lttng_list_interrupts(session);
 711         if (ret)
 712                 return ret;
 713         ret = lttng_enumerate_network_ip_interface(session);
 714         if (ret)
 715                 return ret;
 716         ret = lttng_enumerate_block_devices(session);
 717         switch (ret) {
 718         case 0:
 719                 break;
 720         case -ENOSYS:
 721                 printk(KERN_WARNING "LTTng: block device enumeration is not supported by kernel\n");
 722                 break;
 723         default:
 724                 return ret;
 725         }
 726         ret = lttng_enumerate_cpu_topology(session);
 727         if (ret)
 728                 return ret;
 729
 730         /* TODO lttng_dump_idt_table(session); */
 731         /* TODO lttng_dump_softirq_vec(session); */
 732         /* TODO lttng_list_modules(session); */
 733         /* TODO lttng_dump_swap_files(session); */
 734
 735         /*
 736          * Fire off a work queue on each CPU. Their sole purpose in life
 737          * is to guarantee that each CPU has been in a state where is was in
 738          * syscall mode (i.e. not in a trap, an IRQ or a soft IRQ).
 739          */
 740         get_online_cpus();
 741         atomic_set(&kernel_threads_to_run, num_online_cpus());
 742         for_each_online_cpu(cpu) {
 743                 INIT_DELAYED_WORK(&cpu_work[cpu], lttng_statedump_work_func);
 744                 schedule_delayed_work_on(cpu, &cpu_work[cpu], 0);
 745         }
 746         /* Wait for all threads to run */
 747         __wait_event(statedump_wq, (atomic_read(&kernel_threads_to_run) == 0));
 748         put_online_cpus();
 749         /* Our work is done */
 750         trace_lttng_statedump_end(session);
 751         return 0;
 752 }
 753
 754 /*
 755  * Called with session mutex held.
 756  */
 757 int lttng_statedump_start(struct lttng_kernel_session *session)
 758 {
 759         return do_lttng_statedump(session);
 760 }
 761 EXPORT_SYMBOL_GPL(lttng_statedump_start);
 762
 763 static
 764 int __init lttng_statedump_init(void)
 765 {
 766         /*
 767          * Allow module to load even if the fixup cannot be done. This
 768          * will allow seemless transition when the underlying issue fix
 769          * is merged into the Linux kernel, and when tracepoint.c
 770          * "tracepoint_module_notify" is turned into a static function.
 771          */
 772         (void) wrapper_lttng_fixup_sig(THIS_MODULE);
 773         return 0;
 774 }
 775
 776 module_init(lttng_statedump_init);
 777
 778 static
 779 void __exit lttng_statedump_exit(void)
 780 {
 781 }
 782
 783 module_exit(lttng_statedump_exit);
 784
 785 MODULE_LICENSE("GPL and additional rights");
 786 MODULE_AUTHOR("Jean-Hugues Deschenes");
 787 MODULE_DESCRIPTION("LTTng statedump provider");
 788 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
 789         __stringify(LTTNG_MODULES_MINOR_VERSION) "."
 790         __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
 791         LTTNG_MODULES_EXTRAVERSION);