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 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,12,0))
 253 static
 254 int lttng_statedump_each_block_device(struct lttng_kernel_session *session, struct gendisk *disk)
 255 {
 256         struct block_device *part;
 257         unsigned long idx;
 258         int ret = 0;
 259
 260         /* Include partition 0 */
 261         idx = 0;
 262
 263         rcu_read_lock();
 264         xa_for_each(&disk->part_tbl, idx, part) {
 265                 char name_buf[BDEVNAME_SIZE];
 266
 267                 /* Exclude non-partitions bdev and empty partitions. */
 268                 if (bdev_is_partition(part) && !bdev_nr_sectors(part))
 269                         continue;
 270
 271                 if (lttng_get_part_name(disk, part, name_buf) == -ENOSYS) {
 272                         ret = -ENOSYS;
 273                         goto end;
 274                 }
 275                 trace_lttng_statedump_block_device(session, lttng_get_part_devt(part),
 276                                 name_buf);
 277         }
 278 end:
 279         rcu_read_unlock();
 280         return ret;
 281 }
 282 #else
 283 static
 284 int lttng_statedump_each_block_device(struct lttng_kernel_session *session, struct gendisk *disk)
 285 {
 286         struct disk_part_iter piter;
 287         LTTNG_PART_STRUCT_TYPE *part;
 288
 289         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
 290
 291         while ((part = disk_part_iter_next(&piter))) {
 292                 char name_buf[BDEVNAME_SIZE];
 293
 294                 if (lttng_get_part_name(disk, part, name_buf) == -ENOSYS) {
 295                         disk_part_iter_exit(&piter);
 296                         return -ENOSYS;
 297                 }
 298                 trace_lttng_statedump_block_device(session, lttng_get_part_devt(part),
 299                                 name_buf);
 300         }
 301         disk_part_iter_exit(&piter);
 302
 303         return 0;
 304 }
 305 #endif
 306
 307 static
 308 int lttng_enumerate_block_devices(struct lttng_kernel_session *session)
 309 {
 310         struct class *ptr_block_class;
 311         struct device_type *ptr_disk_type;
 312         struct class_dev_iter iter;
 313         struct device *dev;
 314         int ret = 0;
 315
 316         ptr_block_class = wrapper_get_block_class();
 317         if (!ptr_block_class) {
 318                 ret = -ENOSYS;
 319                 goto end;
 320         }
 321         ptr_disk_type = wrapper_get_disk_type();
 322         if (!ptr_disk_type) {
 323                 ret = -ENOSYS;
 324                 goto end;
 325         }
 326         class_dev_iter_init(&iter, ptr_block_class, NULL, ptr_disk_type);
 327         while ((dev = class_dev_iter_next(&iter))) {
 328                 struct gendisk *disk = dev_to_disk(dev);
 329
 330                 /*
 331                  * Don't show empty devices or things that have been
 332                  * suppressed
 333                  */
 334                 if (get_capacity(disk) == 0 ||
 335                     (disk->flags & GENHD_FL_SUPPRESS_PARTITION_INFO))
 336                         continue;
 337
 338                 ret = lttng_statedump_each_block_device(session, disk);
 339         }
 340         class_dev_iter_exit(&iter);
 341 end:
 342         return ret;
 343 }
 344
 345 #ifdef CONFIG_INET
 346
 347 static
 348 void lttng_enumerate_device(struct lttng_kernel_session *session,
 349                 struct net_device *dev)
 350 {
 351         struct in_device *in_dev;
 352         struct in_ifaddr *ifa;
 353
 354         if (dev->flags & IFF_UP) {
 355                 in_dev = in_dev_get(dev);
 356                 if (in_dev) {
 357                         for (ifa = in_dev->ifa_list; ifa != NULL;
 358                              ifa = ifa->ifa_next) {
 359                                 trace_lttng_statedump_network_interface(
 360                                         session, dev, ifa);
 361                         }
 362                         in_dev_put(in_dev);
 363                 }
 364         } else {
 365                 trace_lttng_statedump_network_interface(
 366                         session, dev, NULL);
 367         }
 368 }
 369
 370 static
 371 int lttng_enumerate_network_ip_interface(struct lttng_kernel_session *session)
 372 {
 373         struct net_device *dev;
 374
 375         read_lock(&dev_base_lock);
 376         for_each_netdev(&init_net, dev)
 377                 lttng_enumerate_device(session, dev);
 378         read_unlock(&dev_base_lock);
 379
 380         return 0;
 381 }
 382 #else /* CONFIG_INET */
 383 static inline
 384 int lttng_enumerate_network_ip_interface(struct lttng_kernel_session *session)
 385 {
 386         return 0;
 387 }
 388 #endif /* CONFIG_INET */
 389
 390 static
 391 int lttng_dump_one_fd(const void *p, struct file *file, unsigned int fd)
 392 {
 393         const struct lttng_fd_ctx *ctx = p;
 394         const char *s = d_path(&file->f_path, ctx->page, PAGE_SIZE);
 395         unsigned int flags = file->f_flags;
 396         struct fdtable *fdt;
 397
 398         /*
 399          * We don't expose kernel internal flags, only userspace-visible
 400          * flags.
 401          */
 402         flags &= ~FMODE_NONOTIFY;
 403         fdt = files_fdtable(ctx->files);
 404         /*
 405          * We need to check here again whether fd is within the fdt
 406          * max_fds range, because we might be seeing a different
 407          * files_fdtable() than iterate_fd(), assuming only RCU is
 408          * protecting the read. In reality, iterate_fd() holds
 409          * file_lock, which should ensure the fdt does not change while
 410          * the lock is taken, but we are not aware whether this is
 411          * guaranteed or not, so play safe.
 412          */
 413         if (fd < fdt->max_fds && lttng_close_on_exec(fd, fdt))
 414                 flags |= O_CLOEXEC;
 415         if (IS_ERR(s)) {
 416                 struct dentry *dentry = file->f_path.dentry;
 417
 418                 /* Make sure we give at least some info */
 419                 spin_lock(&dentry->d_lock);
 420                 trace_lttng_statedump_file_descriptor(ctx->session,
 421                         ctx->files, fd, dentry->d_name.name, flags,
 422                         file->f_mode);
 423                 spin_unlock(&dentry->d_lock);
 424                 goto end;
 425         }
 426         trace_lttng_statedump_file_descriptor(ctx->session,
 427                 ctx->files, fd, s, flags, file->f_mode);
 428 end:
 429         return 0;
 430 }
 431
 432 /* Called with task lock held. */
 433 static
 434 void lttng_enumerate_files(struct lttng_kernel_session *session,
 435                 struct files_struct *files,
 436                 char *tmp)
 437 {
 438         struct lttng_fd_ctx ctx = { .page = tmp, .session = session, .files = files, };
 439
 440         lttng_iterate_fd(files, 0, lttng_dump_one_fd, &ctx);
 441 }
 442
 443 #ifdef LTTNG_HAVE_STATEDUMP_CPU_TOPOLOGY
 444 static
 445 int lttng_enumerate_cpu_topology(struct lttng_kernel_session *session)
 446 {
 447         int cpu;
 448         const cpumask_t *cpumask = cpu_possible_mask;
 449
 450         for (cpu = cpumask_first(cpumask); cpu < nr_cpu_ids;
 451                         cpu = cpumask_next(cpu, cpumask)) {
 452                 trace_lttng_statedump_cpu_topology(session, &cpu_data(cpu));
 453         }
 454
 455         return 0;
 456 }
 457 #else
 458 static
 459 int lttng_enumerate_cpu_topology(struct lttng_kernel_session *session)
 460 {
 461         return 0;
 462 }
 463 #endif
 464
 465 #if 0
 466 /*
 467  * FIXME: we cannot take a mmap_sem while in a RCU read-side critical section
 468  * (scheduling in atomic). Normally, the tasklist lock protects this kind of
 469  * iteration, but it is not exported to modules.
 470  */
 471 static
 472 void lttng_enumerate_task_vm_maps(struct lttng_kernel_session *session,
 473                 struct task_struct *p)
 474 {
 475         struct mm_struct *mm;
 476         struct vm_area_struct *map;
 477         unsigned long ino;
 478
 479         /* get_task_mm does a task_lock... */
 480         mm = get_task_mm(p);
 481         if (!mm)
 482                 return;
 483
 484         map = mm->mmap;
 485         if (map) {
 486                 down_read(&mm->mmap_sem);
 487                 while (map) {
 488                         if (map->vm_file)
 489                                 ino = map->vm_file->lttng_f_dentry->d_inode->i_ino;
 490                         else
 491                                 ino = 0;
 492                         trace_lttng_statedump_vm_map(session, p, map, ino);
 493                         map = map->vm_next;
 494                 }
 495                 up_read(&mm->mmap_sem);
 496         }
 497         mmput(mm);
 498 }
 499
 500 static
 501 int lttng_enumerate_vm_maps(struct lttng_kernel_session *session)
 502 {
 503         struct task_struct *p;
 504
 505         rcu_read_lock();
 506         for_each_process(p)
 507                 lttng_enumerate_task_vm_maps(session, p);
 508         rcu_read_unlock();
 509         return 0;
 510 }
 511 #endif
 512
 513 #ifdef CONFIG_LTTNG_HAS_LIST_IRQ
 514
 515 static
 516 int lttng_list_interrupts(struct lttng_kernel_session *session)
 517 {
 518         unsigned int irq;
 519         unsigned long flags = 0;
 520         struct irq_desc *desc;
 521
 522 #define irq_to_desc     wrapper_irq_to_desc
 523         /* needs irq_desc */
 524         for_each_irq_desc(irq, desc) {
 525                 struct irqaction *action;
 526                 const char *irq_chip_name =
 527                         irq_desc_get_chip(desc)->name ? : "unnamed_irq_chip";
 528
 529                 local_irq_save(flags);
 530                 raw_spin_lock(&desc->lock);
 531                 for (action = desc->action; action; action = action->next) {
 532                         trace_lttng_statedump_interrupt(session,
 533                                 irq, irq_chip_name, action);
 534                 }
 535                 raw_spin_unlock(&desc->lock);
 536                 local_irq_restore(flags);
 537         }
 538         return 0;
 539 #undef irq_to_desc
 540 }
 541 #else
 542 static inline
 543 int lttng_list_interrupts(struct lttng_kernel_session *session)
 544 {
 545         return 0;
 546 }
 547 #endif
 548
 549 /*
 550  * Statedump the task's namespaces using the proc filesystem inode number as
 551  * the unique identifier. The user and pid ns are nested and will be dumped
 552  * recursively.
 553  *
 554  * Called with task lock held.
 555  */
 556 static
 557 void lttng_statedump_process_ns(struct lttng_kernel_session *session,
 558                 struct task_struct *p,
 559                 enum lttng_thread_type type,
 560                 enum lttng_execution_mode mode,
 561                 enum lttng_execution_submode submode,
 562                 enum lttng_process_status status)
 563 {
 564         struct nsproxy *proxy;
 565         struct pid_namespace *pid_ns;
 566         struct user_namespace *user_ns;
 567
 568         /*
 569          * The pid and user namespaces are special, they are nested and
 570          * accessed with specific functions instead of the nsproxy struct
 571          * like the other namespaces.
 572          */
 573         pid_ns = task_active_pid_ns(p);
 574         do {
 575                 trace_lttng_statedump_process_pid_ns(session, p, pid_ns);
 576                 pid_ns = pid_ns ? pid_ns->parent : NULL;
 577         } while (pid_ns);
 578
 579
 580         user_ns = task_cred_xxx(p, user_ns);
 581         do {
 582                 trace_lttng_statedump_process_user_ns(session, p, user_ns);
 583                 /*
 584                  * trace_lttng_statedump_process_user_ns() internally
 585                  * checks whether user_ns is NULL. While this does not
 586                  * appear to be a possible return value for
 587                  * task_cred_xxx(), err on the safe side and check
 588                  * for NULL here as well to be consistent with the
 589                  * paranoid behavior of
 590                  * trace_lttng_statedump_process_user_ns().
 591                  */
 592                 user_ns = user_ns ? user_ns->lttng_user_ns_parent : NULL;
 593         } while (user_ns);
 594
 595         /*
 596          * Back and forth on locking strategy within Linux upstream for nsproxy.
 597          * See Linux upstream commit 728dba3a39c66b3d8ac889ddbe38b5b1c264aec3
 598          * "namespaces: Use task_lock and not rcu to protect nsproxy"
 599          * for details.
 600          */
 601 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,17,0) || \
 602                 LTTNG_UBUNTU_KERNEL_RANGE(3,13,11,36, 3,14,0,0) || \
 603                 LTTNG_UBUNTU_KERNEL_RANGE(3,16,1,11, 3,17,0,0) || \
 604                 LTTNG_RHEL_KERNEL_RANGE(3,10,0,229,13,0, 3,11,0,0,0,0))
 605         proxy = p->nsproxy;
 606 #else
 607         rcu_read_lock();
 608         proxy = task_nsproxy(p);
 609 #endif
 610         if (proxy) {
 611 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,6,0))
 612                 trace_lttng_statedump_process_cgroup_ns(session, p, proxy->cgroup_ns);
 613 #endif
 614                 trace_lttng_statedump_process_ipc_ns(session, p, proxy->ipc_ns);
 615 #ifndef LTTNG_MNT_NS_MISSING_HEADER
 616                 trace_lttng_statedump_process_mnt_ns(session, p, proxy->mnt_ns);
 617 #endif
 618                 trace_lttng_statedump_process_net_ns(session, p, proxy->net_ns);
 619                 trace_lttng_statedump_process_uts_ns(session, p, proxy->uts_ns);
 620 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,6,0))
 621                 trace_lttng_statedump_process_time_ns(session, p, proxy->time_ns);
 622 #endif
 623         }
 624 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,17,0) || \
 625                 LTTNG_UBUNTU_KERNEL_RANGE(3,13,11,36, 3,14,0,0) || \
 626                 LTTNG_UBUNTU_KERNEL_RANGE(3,16,1,11, 3,17,0,0) || \
 627                 LTTNG_RHEL_KERNEL_RANGE(3,10,0,229,13,0, 3,11,0,0,0,0))
 628         /* (nothing) */
 629 #else
 630         rcu_read_unlock();
 631 #endif
 632 }
 633
 634 static
 635 int lttng_enumerate_process_states(struct lttng_kernel_session *session)
 636 {
 637         struct task_struct *g, *p;
 638         char *tmp;
 639
 640         tmp = (char *) __get_free_page(GFP_KERNEL);
 641         if (!tmp)
 642                 return -ENOMEM;
 643
 644         rcu_read_lock();
 645         for_each_process(g) {
 646                 struct files_struct *prev_files = NULL;
 647
 648                 p = g;
 649                 do {
 650                         enum lttng_execution_mode mode =
 651                                 LTTNG_MODE_UNKNOWN;
 652                         enum lttng_execution_submode submode =
 653                                 LTTNG_UNKNOWN;
 654                         enum lttng_process_status status;
 655                         enum lttng_thread_type type;
 656                         struct files_struct *files;
 657
 658                         task_lock(p);
 659                         if (p->exit_state == EXIT_ZOMBIE)
 660                                 status = LTTNG_ZOMBIE;
 661                         else if (p->exit_state == EXIT_DEAD)
 662                                 status = LTTNG_DEAD;
 663                         else if (p->state == TASK_RUNNING) {
 664                                 /* Is this a forked child that has not run yet? */
 665                                 if (list_empty(&p->rt.run_list))
 666                                         status = LTTNG_WAIT_FORK;
 667                                 else
 668                                         /*
 669                                          * All tasks are considered as wait_cpu;
 670                                          * the viewer will sort out if the task
 671                                          * was really running at this time.
 672                                          */
 673                                         status = LTTNG_WAIT_CPU;
 674                         } else if (p->state &
 675                                 (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)) {
 676                                 /* Task is waiting for something to complete */
 677                                 status = LTTNG_WAIT;
 678                         } else
 679                                 status = LTTNG_UNNAMED;
 680                         submode = LTTNG_NONE;
 681
 682                         /*
 683                          * Verification of t->mm is to filter out kernel
 684                          * threads; Viewer will further filter out if a
 685                          * user-space thread was in syscall mode or not.
 686                          */
 687                         if (p->mm)
 688                                 type = LTTNG_USER_THREAD;
 689                         else
 690                                 type = LTTNG_KERNEL_THREAD;
 691                         files = p->files;
 692
 693                         trace_lttng_statedump_process_state(session,
 694                                 p, type, mode, submode, status, files);
 695                         lttng_statedump_process_ns(session,
 696                                 p, type, mode, submode, status);
 697                         /*
 698                          * As an optimisation for the common case, do not
 699                          * repeat information for the same files_struct in
 700                          * two consecutive threads. This is the common case
 701                          * for threads sharing the same fd table. RCU guarantees
 702                          * that the same files_struct pointer is not re-used
 703                          * throughout processes/threads iteration.
 704                          */
 705                         if (files && files != prev_files) {
 706                                 lttng_enumerate_files(session, files, tmp);
 707                                 prev_files = files;
 708                         }
 709                         task_unlock(p);
 710                 } while_each_thread(g, p);
 711         }
 712         rcu_read_unlock();
 713
 714         free_page((unsigned long) tmp);
 715
 716         return 0;
 717 }
 718
 719 static
 720 void lttng_statedump_work_func(struct work_struct *work)
 721 {
 722         if (atomic_dec_and_test(&kernel_threads_to_run))
 723                 /* If we are the last thread, wake up do_lttng_statedump */
 724                 wake_up(&statedump_wq);
 725 }
 726
 727 static
 728 int do_lttng_statedump(struct lttng_kernel_session *session)
 729 {
 730         int cpu, ret;
 731
 732         trace_lttng_statedump_start(session);
 733         ret = lttng_enumerate_process_states(session);
 734         if (ret)
 735                 return ret;
 736         /*
 737          * FIXME
 738          * ret = lttng_enumerate_vm_maps(session);
 739          * if (ret)
 740          *      return ret;
 741          */
 742         ret = lttng_list_interrupts(session);
 743         if (ret)
 744                 return ret;
 745         ret = lttng_enumerate_network_ip_interface(session);
 746         if (ret)
 747                 return ret;
 748         ret = lttng_enumerate_block_devices(session);
 749         switch (ret) {
 750         case 0:
 751                 break;
 752         case -ENOSYS:
 753                 printk(KERN_WARNING "LTTng: block device enumeration is not supported by kernel\n");
 754                 break;
 755         default:
 756                 return ret;
 757         }
 758         ret = lttng_enumerate_cpu_topology(session);
 759         if (ret)
 760                 return ret;
 761
 762         /* TODO lttng_dump_idt_table(session); */
 763         /* TODO lttng_dump_softirq_vec(session); */
 764         /* TODO lttng_list_modules(session); */
 765         /* TODO lttng_dump_swap_files(session); */
 766
 767         /*
 768          * Fire off a work queue on each CPU. Their sole purpose in life
 769          * is to guarantee that each CPU has been in a state where is was in
 770          * syscall mode (i.e. not in a trap, an IRQ or a soft IRQ).
 771          */
 772         get_online_cpus();
 773         atomic_set(&kernel_threads_to_run, num_online_cpus());
 774         for_each_online_cpu(cpu) {
 775                 INIT_DELAYED_WORK(&cpu_work[cpu], lttng_statedump_work_func);
 776                 schedule_delayed_work_on(cpu, &cpu_work[cpu], 0);
 777         }
 778         /* Wait for all threads to run */
 779         __wait_event(statedump_wq, (atomic_read(&kernel_threads_to_run) == 0));
 780         put_online_cpus();
 781         /* Our work is done */
 782         trace_lttng_statedump_end(session);
 783         return 0;
 784 }
 785
 786 /*
 787  * Called with session mutex held.
 788  */
 789 int lttng_statedump_start(struct lttng_kernel_session *session)
 790 {
 791         return do_lttng_statedump(session);
 792 }
 793 EXPORT_SYMBOL_GPL(lttng_statedump_start);
 794
 795 static
 796 int __init lttng_statedump_init(void)
 797 {
 798         /*
 799          * Allow module to load even if the fixup cannot be done. This
 800          * will allow seemless transition when the underlying issue fix
 801          * is merged into the Linux kernel, and when tracepoint.c
 802          * "tracepoint_module_notify" is turned into a static function.
 803          */
 804         (void) wrapper_lttng_fixup_sig(THIS_MODULE);
 805         return 0;
 806 }
 807
 808 module_init(lttng_statedump_init);
 809
 810 static
 811 void __exit lttng_statedump_exit(void)
 812 {
 813 }
 814
 815 module_exit(lttng_statedump_exit);
 816
 817 MODULE_LICENSE("GPL and additional rights");
 818 MODULE_AUTHOR("Jean-Hugues Deschenes");
 819 MODULE_DESCRIPTION("LTTng statedump provider");
 820 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
 821         __stringify(LTTNG_MODULES_MINOR_VERSION) "."
 822         __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
 823         LTTNG_MODULES_EXTRAVERSION);