lttng-statedump-impl.c

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