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