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/netdevice.h>
  27 #include <linux/inetdevice.h>
  28 #include <linux/mm.h>
  29 #include <linux/swap.h>
  30 #include <linux/wait.h>
  31 #include <linux/mutex.h>
  32 #include <linux/device.h>
  33
  34 #include <linux/blkdev.h>
  35
  36 #include <lttng/events.h>
  37 #include <lttng/tracer.h>
  38 #include <wrapper/cpu.h>
  39 #include <wrapper/irqdesc.h>
  40 #include <wrapper/fdtable.h>
  41 #include <wrapper/namespace.h>
  42 #include <wrapper/irq.h>
  43 #include <wrapper/tracepoint.h>
  44 #include <wrapper/blkdev.h>
  45 #include <wrapper/fdtable.h>
  46 #include <wrapper/sched.h>
  47
  48 #ifdef CONFIG_LTTNG_HAS_LIST_IRQ
  49 #include <linux/irq.h>
  50 #endif
  51
  52 /* Define the tracepoints, but do not build the probes */
  53 #define CREATE_TRACE_POINTS
  54 #define TRACE_INCLUDE_PATH instrumentation/events
  55 #define TRACE_INCLUDE_FILE lttng-statedump
  56 #define LTTNG_INSTRUMENTATION
  57 #include <instrumentation/events/lttng-statedump.h>
  58
  59 LTTNG_DEFINE_TRACE(lttng_statedump_block_device,
  60         TP_PROTO(struct lttng_kernel_session *session,
  61                 dev_t dev, const char *diskname),
  62         TP_ARGS(session, dev, diskname));
  63
  64 LTTNG_DEFINE_TRACE(lttng_statedump_end,
  65         TP_PROTO(struct lttng_kernel_session *session),
  66         TP_ARGS(session));
  67
  68 LTTNG_DEFINE_TRACE(lttng_statedump_interrupt,
  69         TP_PROTO(struct lttng_kernel_session *session,
  70                 unsigned int irq, const char *chip_name,
  71                 struct irqaction *action),
  72         TP_ARGS(session, irq, chip_name, action));
  73
  74 LTTNG_DEFINE_TRACE(lttng_statedump_file_descriptor,
  75         TP_PROTO(struct lttng_kernel_session *session,
  76                 struct files_struct *files,
  77                 int fd, const char *filename,
  78                 unsigned int flags, fmode_t fmode),
  79         TP_ARGS(session, files, fd, filename, flags, fmode));
  80
  81 LTTNG_DEFINE_TRACE(lttng_statedump_start,
  82         TP_PROTO(struct lttng_kernel_session *session),
  83         TP_ARGS(session));
  84
  85 LTTNG_DEFINE_TRACE(lttng_statedump_process_state,
  86         TP_PROTO(struct lttng_kernel_session *session,
  87                 struct task_struct *p,
  88                 int type, int mode, int submode, int status,
  89                 struct files_struct *files),
  90         TP_ARGS(session, p, type, mode, submode, status, files));
  91
  92 LTTNG_DEFINE_TRACE(lttng_statedump_process_pid_ns,
  93         TP_PROTO(struct lttng_kernel_session *session,
  94                 struct task_struct *p,
  95                 struct pid_namespace *pid_ns),
  96         TP_ARGS(session, p, pid_ns));
  97
  98 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,6,0))
  99 LTTNG_DEFINE_TRACE(lttng_statedump_process_cgroup_ns,
 100         TP_PROTO(struct lttng_kernel_session *session,
 101                 struct task_struct *p,
 102                 struct cgroup_namespace *cgroup_ns),
 103         TP_ARGS(session, p, cgroup_ns));
 104 #endif
 105
 106 LTTNG_DEFINE_TRACE(lttng_statedump_process_ipc_ns,
 107         TP_PROTO(struct lttng_kernel_session *session,
 108                 struct task_struct *p,
 109                 struct ipc_namespace *ipc_ns),
 110         TP_ARGS(session, p, ipc_ns));
 111
 112 #ifndef LTTNG_MNT_NS_MISSING_HEADER
 113 LTTNG_DEFINE_TRACE(lttng_statedump_process_mnt_ns,
 114         TP_PROTO(struct lttng_kernel_session *session,
 115                 struct task_struct *p,
 116                 struct mnt_namespace *mnt_ns),
 117         TP_ARGS(session, p, mnt_ns));
 118 #endif
 119
 120 LTTNG_DEFINE_TRACE(lttng_statedump_process_net_ns,
 121         TP_PROTO(struct lttng_kernel_session *session,
 122                 struct task_struct *p,
 123                 struct net *net_ns),
 124         TP_ARGS(session, p, net_ns));
 125
 126 LTTNG_DEFINE_TRACE(lttng_statedump_process_user_ns,
 127         TP_PROTO(struct lttng_kernel_session *session,
 128                 struct task_struct *p,
 129                 struct user_namespace *user_ns),
 130         TP_ARGS(session, p, user_ns));
 131
 132 LTTNG_DEFINE_TRACE(lttng_statedump_process_uts_ns,
 133         TP_PROTO(struct lttng_kernel_session *session,
 134                 struct task_struct *p,
 135                 struct uts_namespace *uts_ns),
 136         TP_ARGS(session, p, uts_ns));
 137
 138 LTTNG_DEFINE_TRACE(lttng_statedump_process_time_ns,
 139         TP_PROTO(struct lttng_kernel_session *session,
 140                 struct task_struct *p,
 141                 struct time_namespace *time_ns),
 142         TP_ARGS(session, p, time_ns));
 143
 144 LTTNG_DEFINE_TRACE(lttng_statedump_network_interface,
 145         TP_PROTO(struct lttng_kernel_session *session,
 146                 struct net_device *dev, struct in_ifaddr *ifa),
 147         TP_ARGS(session, dev, ifa));
 148
 149 #ifdef LTTNG_HAVE_STATEDUMP_CPU_TOPOLOGY
 150 LTTNG_DEFINE_TRACE(lttng_statedump_cpu_topology,
 151         TP_PROTO(struct lttng_kernel_session *session, struct cpuinfo_x86 *c),
 152         TP_ARGS(session, c));
 153 #endif
 154
 155 struct lttng_fd_ctx {
 156         char *page;
 157         struct lttng_kernel_session *session;
 158         struct files_struct *files;
 159 };
 160
 161 /*
 162  * Protected by the trace lock.
 163  */
 164 static struct delayed_work cpu_work[NR_CPUS];
 165 static DECLARE_WAIT_QUEUE_HEAD(statedump_wq);
 166 static atomic_t kernel_threads_to_run;
 167
 168 enum lttng_thread_type {
 169         LTTNG_USER_THREAD = 0,
 170         LTTNG_KERNEL_THREAD = 1,
 171 };
 172
 173 enum lttng_execution_mode {
 174         LTTNG_USER_MODE = 0,
 175         LTTNG_SYSCALL = 1,
 176         LTTNG_TRAP = 2,
 177         LTTNG_IRQ = 3,
 178         LTTNG_SOFTIRQ = 4,
 179         LTTNG_MODE_UNKNOWN = 5,
 180 };
 181
 182 enum lttng_execution_submode {
 183         LTTNG_NONE = 0,
 184         LTTNG_UNKNOWN = 1,
 185 };
 186
 187 enum lttng_process_status {
 188         LTTNG_UNNAMED = 0,
 189         LTTNG_WAIT_FORK = 1,
 190         LTTNG_WAIT_CPU = 2,
 191         LTTNG_EXIT = 3,
 192         LTTNG_ZOMBIE = 4,
 193         LTTNG_WAIT = 5,
 194         LTTNG_RUN = 6,
 195         LTTNG_DEAD = 7,
 196 };
 197
 198
 199 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(6,0,0))
 200
 201 #define LTTNG_PART_STRUCT_TYPE struct block_device
 202
 203 static
 204 int lttng_get_part_name(struct gendisk *disk, struct block_device *part, char *name_buf)
 205 {
 206         int ret;
 207
 208         ret = snprintf(name_buf, BDEVNAME_SIZE, "%pg", part);
 209         if (ret < 0 || ret >= BDEVNAME_SIZE)
 210                 return -ENOSYS;
 211
 212         return 0;
 213 }
 214
 215 static
 216 dev_t lttng_get_part_devt(struct block_device *part)
 217 {
 218         return part->bd_dev;
 219 }
 220
 221 #elif (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,11,0))
 222
 223 #define LTTNG_PART_STRUCT_TYPE struct block_device
 224
 225 static
 226 int lttng_get_part_name(struct gendisk *disk, struct block_device *part, char *name_buf)
 227 {
 228         const char *p;
 229
 230         p = bdevname(part, name_buf);
 231         if (!p)
 232                 return -ENOSYS;
 233
 234         return 0;
 235 }
 236
 237 static
 238 dev_t lttng_get_part_devt(struct block_device *part)
 239 {
 240         return part->bd_dev;
 241 }
 242
 243 #else
 244
 245 #define LTTNG_PART_STRUCT_TYPE struct hd_struct
 246
 247 static
 248 int lttng_get_part_name(struct gendisk *disk, struct hd_struct *part, char *name_buf)
 249 {
 250         const char *p;
 251         struct block_device bdev;
 252
 253         /*
 254          * Create a partial 'struct blockdevice' to use
 255          * 'bdevname()' which is a simple wrapper over
 256          * 'disk_name()' but has the honor to be EXPORT_SYMBOL.
 257          */
 258         bdev.bd_disk = disk;
 259         bdev.bd_part = part;
 260
 261         p = bdevname(&bdev, name_buf);
 262         if (!p)
 263                 return -ENOSYS;
 264
 265         return 0;
 266 }
 267
 268 static
 269 dev_t lttng_get_part_devt(struct hd_struct *part)
 270 {
 271         return part_devt(part);
 272 }
 273 #endif
 274
 275 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,12,0))
 276 static
 277 int lttng_statedump_each_block_device(struct lttng_kernel_session *session, struct gendisk *disk)
 278 {
 279         struct block_device *part;
 280         unsigned long idx;
 281         int ret = 0;
 282
 283         /* Include partition 0 */
 284         idx = 0;
 285
 286         rcu_read_lock();
 287         xa_for_each(&disk->part_tbl, idx, part) {
 288                 char name_buf[BDEVNAME_SIZE];
 289
 290                 /* Exclude non-partitions bdev and empty partitions. */
 291                 if (bdev_is_partition(part) && !bdev_nr_sectors(part))
 292                         continue;
 293
 294                 if (lttng_get_part_name(disk, part, name_buf) == -ENOSYS) {
 295                         ret = -ENOSYS;
 296                         goto end;
 297                 }
 298                 trace_lttng_statedump_block_device(session, lttng_get_part_devt(part),
 299                                 name_buf);
 300         }
 301 end:
 302         rcu_read_unlock();
 303         return ret;
 304 }
 305 #else
 306 static
 307 int lttng_statedump_each_block_device(struct lttng_kernel_session *session, struct gendisk *disk)
 308 {
 309         struct disk_part_iter piter;
 310         LTTNG_PART_STRUCT_TYPE *part;
 311
 312         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
 313
 314         while ((part = disk_part_iter_next(&piter))) {
 315                 char name_buf[BDEVNAME_SIZE];
 316
 317                 if (lttng_get_part_name(disk, part, name_buf) == -ENOSYS) {
 318                         disk_part_iter_exit(&piter);
 319                         return -ENOSYS;
 320                 }
 321                 trace_lttng_statedump_block_device(session, lttng_get_part_devt(part),
 322                                 name_buf);
 323         }
 324         disk_part_iter_exit(&piter);
 325
 326         return 0;
 327 }
 328 #endif
 329
 330 static
 331 int lttng_enumerate_block_devices(struct lttng_kernel_session *session)
 332 {
 333         struct class *ptr_block_class;
 334         struct device_type *ptr_disk_type;
 335         struct class_dev_iter iter;
 336         struct device *dev;
 337         int ret = 0;
 338
 339         ptr_block_class = wrapper_get_block_class();
 340         if (!ptr_block_class) {
 341                 ret = -ENOSYS;
 342                 goto end;
 343         }
 344         ptr_disk_type = wrapper_get_disk_type();
 345         if (!ptr_disk_type) {
 346                 ret = -ENOSYS;
 347                 goto end;
 348         }
 349         class_dev_iter_init(&iter, ptr_block_class, NULL, ptr_disk_type);
 350         while ((dev = class_dev_iter_next(&iter))) {
 351                 struct gendisk *disk = dev_to_disk(dev);
 352
 353                 /*
 354                  * Don't show empty devices or things that have been
 355                  * suppressed
 356                  */
 357                 if (get_capacity(disk) == 0 ||
 358                     (disk->flags & LTTNG_GENHD_FL_HIDDEN))
 359                         continue;
 360
 361                 ret = lttng_statedump_each_block_device(session, disk);
 362         }
 363         class_dev_iter_exit(&iter);
 364 end:
 365         return ret;
 366 }
 367
 368 #ifdef CONFIG_INET
 369
 370 static
 371 void lttng_enumerate_device(struct lttng_kernel_session *session,
 372                 struct net_device *dev)
 373 {
 374         struct in_device *in_dev;
 375         struct in_ifaddr *ifa;
 376
 377         if (dev->flags & IFF_UP) {
 378                 in_dev = in_dev_get(dev);
 379                 if (in_dev) {
 380                         for (ifa = in_dev->ifa_list; ifa != NULL;
 381                              ifa = ifa->ifa_next) {
 382                                 trace_lttng_statedump_network_interface(
 383                                         session, dev, ifa);
 384                         }
 385                         in_dev_put(in_dev);
 386                 }
 387         } else {
 388                 trace_lttng_statedump_network_interface(
 389                         session, dev, NULL);
 390         }
 391 }
 392
 393 static
 394 int lttng_enumerate_network_ip_interface(struct lttng_kernel_session *session)
 395 {
 396         struct net_device *dev;
 397
 398         read_lock(&dev_base_lock);
 399         for_each_netdev(&init_net, dev)
 400                 lttng_enumerate_device(session, dev);
 401         read_unlock(&dev_base_lock);
 402
 403         return 0;
 404 }
 405 #else /* CONFIG_INET */
 406 static inline
 407 int lttng_enumerate_network_ip_interface(struct lttng_kernel_session *session)
 408 {
 409         return 0;
 410 }
 411 #endif /* CONFIG_INET */
 412
 413 static
 414 int lttng_dump_one_fd(const void *p, struct file *file, unsigned int fd)
 415 {
 416         const struct lttng_fd_ctx *ctx = p;
 417         const char *s = d_path(&file->f_path, ctx->page, PAGE_SIZE);
 418         unsigned int flags = file->f_flags;
 419         struct fdtable *fdt;
 420
 421         /*
 422          * We don't expose kernel internal flags, only userspace-visible
 423          * flags.
 424          */
 425         flags &= ~FMODE_NONOTIFY;
 426         fdt = files_fdtable(ctx->files);
 427         /*
 428          * We need to check here again whether fd is within the fdt
 429          * max_fds range, because we might be seeing a different
 430          * files_fdtable() than iterate_fd(), assuming only RCU is
 431          * protecting the read. In reality, iterate_fd() holds
 432          * file_lock, which should ensure the fdt does not change while
 433          * the lock is taken, but we are not aware whether this is
 434          * guaranteed or not, so play safe.
 435          */
 436         if (fd < fdt->max_fds && lttng_close_on_exec(fd, fdt))
 437                 flags |= O_CLOEXEC;
 438         if (IS_ERR(s)) {
 439                 struct dentry *dentry = file->f_path.dentry;
 440
 441                 /* Make sure we give at least some info */
 442                 spin_lock(&dentry->d_lock);
 443                 trace_lttng_statedump_file_descriptor(ctx->session,
 444                         ctx->files, fd, dentry->d_name.name, flags,
 445                         file->f_mode);
 446                 spin_unlock(&dentry->d_lock);
 447                 goto end;
 448         }
 449         trace_lttng_statedump_file_descriptor(ctx->session,
 450                 ctx->files, fd, s, flags, file->f_mode);
 451 end:
 452         return 0;
 453 }
 454
 455 /* Called with task lock held. */
 456 static
 457 void lttng_enumerate_files(struct lttng_kernel_session *session,
 458                 struct files_struct *files,
 459                 char *tmp)
 460 {
 461         struct lttng_fd_ctx ctx = { .page = tmp, .session = session, .files = files, };
 462
 463         lttng_iterate_fd(files, 0, lttng_dump_one_fd, &ctx);
 464 }
 465
 466 #ifdef LTTNG_HAVE_STATEDUMP_CPU_TOPOLOGY
 467 static
 468 int lttng_enumerate_cpu_topology(struct lttng_kernel_session *session)
 469 {
 470         int cpu;
 471         const cpumask_t *cpumask = cpu_possible_mask;
 472
 473         for (cpu = cpumask_first(cpumask); cpu < nr_cpu_ids;
 474                         cpu = cpumask_next(cpu, cpumask)) {
 475                 trace_lttng_statedump_cpu_topology(session, &cpu_data(cpu));
 476         }
 477
 478         return 0;
 479 }
 480 #else
 481 static
 482 int lttng_enumerate_cpu_topology(struct lttng_kernel_session *session)
 483 {
 484         return 0;
 485 }
 486 #endif
 487
 488 #if 0
 489 /*
 490  * FIXME: we cannot take a mmap_sem while in a RCU read-side critical section
 491  * (scheduling in atomic). Normally, the tasklist lock protects this kind of
 492  * iteration, but it is not exported to modules.
 493  */
 494 static
 495 void lttng_enumerate_task_vm_maps(struct lttng_kernel_session *session,
 496                 struct task_struct *p)
 497 {
 498         struct mm_struct *mm;
 499         struct vm_area_struct *map;
 500         unsigned long ino;
 501
 502         /* get_task_mm does a task_lock... */
 503         mm = get_task_mm(p);
 504         if (!mm)
 505                 return;
 506
 507         map = mm->mmap;
 508         if (map) {
 509                 down_read(&mm->mmap_sem);
 510                 while (map) {
 511                         if (map->vm_file)
 512                                 ino = map->vm_file->f_path.dentry->d_inode->i_ino;
 513                         else
 514                                 ino = 0;
 515                         trace_lttng_statedump_vm_map(session, p, map, ino);
 516                         map = map->vm_next;
 517                 }
 518                 up_read(&mm->mmap_sem);
 519         }
 520         mmput(mm);
 521 }
 522
 523 static
 524 int lttng_enumerate_vm_maps(struct lttng_kernel_session *session)
 525 {
 526         struct task_struct *p;
 527
 528         rcu_read_lock();
 529         for_each_process(p)
 530                 lttng_enumerate_task_vm_maps(session, p);
 531         rcu_read_unlock();
 532         return 0;
 533 }
 534 #endif
 535
 536 #ifdef CONFIG_LTTNG_HAS_LIST_IRQ
 537
 538 static
 539 int lttng_list_interrupts(struct lttng_kernel_session *session)
 540 {
 541         unsigned int irq;
 542         unsigned long flags = 0;
 543         struct irq_desc *desc;
 544
 545 #define irq_to_desc     wrapper_irq_to_desc
 546         /* needs irq_desc */
 547         for_each_irq_desc(irq, desc) {
 548                 struct irqaction *action;
 549                 const char *irq_chip_name =
 550                         irq_desc_get_chip(desc)->name ? : "unnamed_irq_chip";
 551
 552                 local_irq_save(flags);
 553                 raw_spin_lock(&desc->lock);
 554                 for (action = desc->action; action; action = action->next) {
 555                         trace_lttng_statedump_interrupt(session,
 556                                 irq, irq_chip_name, action);
 557                 }
 558                 raw_spin_unlock(&desc->lock);
 559                 local_irq_restore(flags);
 560         }
 561         return 0;
 562 #undef irq_to_desc
 563 }
 564 #else
 565 static inline
 566 int lttng_list_interrupts(struct lttng_kernel_session *session)
 567 {
 568         return 0;
 569 }
 570 #endif
 571
 572 /*
 573  * Statedump the task's namespaces using the proc filesystem inode number as
 574  * the unique identifier. The user and pid ns are nested and will be dumped
 575  * recursively.
 576  *
 577  * Called with task lock held.
 578  */
 579 static
 580 void lttng_statedump_process_ns(struct lttng_kernel_session *session,
 581                 struct task_struct *p,
 582                 enum lttng_thread_type type,
 583                 enum lttng_execution_mode mode,
 584                 enum lttng_execution_submode submode,
 585                 enum lttng_process_status status)
 586 {
 587         struct nsproxy *proxy;
 588         struct pid_namespace *pid_ns;
 589         struct user_namespace *user_ns;
 590
 591         /*
 592          * The pid and user namespaces are special, they are nested and
 593          * accessed with specific functions instead of the nsproxy struct
 594          * like the other namespaces.
 595          */
 596         pid_ns = task_active_pid_ns(p);
 597         do {
 598                 trace_lttng_statedump_process_pid_ns(session, p, pid_ns);
 599                 pid_ns = pid_ns ? pid_ns->parent : NULL;
 600         } while (pid_ns);
 601
 602
 603         user_ns = task_cred_xxx(p, user_ns);
 604         do {
 605                 trace_lttng_statedump_process_user_ns(session, p, user_ns);
 606                 /*
 607                  * trace_lttng_statedump_process_user_ns() internally
 608                  * checks whether user_ns is NULL. While this does not
 609                  * appear to be a possible return value for
 610                  * task_cred_xxx(), err on the safe side and check
 611                  * for NULL here as well to be consistent with the
 612                  * paranoid behavior of
 613                  * trace_lttng_statedump_process_user_ns().
 614                  */
 615                 user_ns = user_ns ? user_ns->lttng_user_ns_parent : NULL;
 616         } while (user_ns);
 617
 618         /*
 619          * Back and forth on locking strategy within Linux upstream for nsproxy.
 620          * See Linux upstream commit 728dba3a39c66b3d8ac889ddbe38b5b1c264aec3
 621          * "namespaces: Use task_lock and not rcu to protect nsproxy"
 622          * for details.
 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         proxy = p->nsproxy;
 629 #else
 630         rcu_read_lock();
 631         proxy = task_nsproxy(p);
 632 #endif
 633         if (proxy) {
 634 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,6,0))
 635                 trace_lttng_statedump_process_cgroup_ns(session, p, proxy->cgroup_ns);
 636 #endif
 637                 trace_lttng_statedump_process_ipc_ns(session, p, proxy->ipc_ns);
 638 #ifndef LTTNG_MNT_NS_MISSING_HEADER
 639                 trace_lttng_statedump_process_mnt_ns(session, p, proxy->mnt_ns);
 640 #endif
 641                 trace_lttng_statedump_process_net_ns(session, p, proxy->net_ns);
 642                 trace_lttng_statedump_process_uts_ns(session, p, proxy->uts_ns);
 643 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,6,0) || \
 644         LTTNG_RHEL_KERNEL_RANGE(4,18,0,305,0,0, 4,19,0,0,0,0))
 645                 trace_lttng_statedump_process_time_ns(session, p, proxy->time_ns);
 646 #endif
 647         }
 648 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,17,0) || \
 649                 LTTNG_UBUNTU_KERNEL_RANGE(3,13,11,36, 3,14,0,0) || \
 650                 LTTNG_UBUNTU_KERNEL_RANGE(3,16,1,11, 3,17,0,0) || \
 651                 LTTNG_RHEL_KERNEL_RANGE(3,10,0,229,13,0, 3,11,0,0,0,0))
 652         /* (nothing) */
 653 #else
 654         rcu_read_unlock();
 655 #endif
 656 }
 657
 658 static
 659 int lttng_enumerate_process_states(struct lttng_kernel_session *session)
 660 {
 661         struct task_struct *g, *p;
 662         char *tmp;
 663
 664         tmp = (char *) __get_free_page(GFP_KERNEL);
 665         if (!tmp)
 666                 return -ENOMEM;
 667
 668         rcu_read_lock();
 669         for_each_process(g) {
 670                 struct files_struct *prev_files = NULL;
 671
 672                 p = g;
 673                 do {
 674                         enum lttng_execution_mode mode =
 675                                 LTTNG_MODE_UNKNOWN;
 676                         enum lttng_execution_submode submode =
 677                                 LTTNG_UNKNOWN;
 678                         enum lttng_process_status status;
 679                         enum lttng_thread_type type;
 680                         struct files_struct *files;
 681
 682                         task_lock(p);
 683                         if (p->exit_state == EXIT_ZOMBIE)
 684                                 status = LTTNG_ZOMBIE;
 685                         else if (p->exit_state == EXIT_DEAD)
 686                                 status = LTTNG_DEAD;
 687                         else if (lttng_task_is_running(p)) {
 688                                 /* Is this a forked child that has not run yet? */
 689                                 if (list_empty(&p->rt.run_list))
 690                                         status = LTTNG_WAIT_FORK;
 691                                 else
 692                                         /*
 693                                          * All tasks are considered as wait_cpu;
 694                                          * the viewer will sort out if the task
 695                                          * was really running at this time.
 696                                          */
 697                                         status = LTTNG_WAIT_CPU;
 698                         } else if (lttng_get_task_state(p) &
 699                                 (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)) {
 700                                 /* Task is waiting for something to complete */
 701                                 status = LTTNG_WAIT;
 702                         } else
 703                                 status = LTTNG_UNNAMED;
 704                         submode = LTTNG_NONE;
 705
 706                         /*
 707                          * Verification of t->mm is to filter out kernel
 708                          * threads; Viewer will further filter out if a
 709                          * user-space thread was in syscall mode or not.
 710                          */
 711                         if (p->mm)
 712                                 type = LTTNG_USER_THREAD;
 713                         else
 714                                 type = LTTNG_KERNEL_THREAD;
 715                         files = p->files;
 716
 717                         trace_lttng_statedump_process_state(session,
 718                                 p, type, mode, submode, status, files);
 719                         lttng_statedump_process_ns(session,
 720                                 p, type, mode, submode, status);
 721                         /*
 722                          * As an optimisation for the common case, do not
 723                          * repeat information for the same files_struct in
 724                          * two consecutive threads. This is the common case
 725                          * for threads sharing the same fd table. RCU guarantees
 726                          * that the same files_struct pointer is not re-used
 727                          * throughout processes/threads iteration.
 728                          */
 729                         if (files && files != prev_files) {
 730                                 lttng_enumerate_files(session, files, tmp);
 731                                 prev_files = files;
 732                         }
 733                         task_unlock(p);
 734                 } while_each_thread(g, p);
 735         }
 736         rcu_read_unlock();
 737
 738         free_page((unsigned long) tmp);
 739
 740         return 0;
 741 }
 742
 743 static
 744 void lttng_statedump_work_func(struct work_struct *work)
 745 {
 746         if (atomic_dec_and_test(&kernel_threads_to_run))
 747                 /* If we are the last thread, wake up do_lttng_statedump */
 748                 wake_up(&statedump_wq);
 749 }
 750
 751 static
 752 int do_lttng_statedump(struct lttng_kernel_session *session)
 753 {
 754         int cpu, ret;
 755
 756         trace_lttng_statedump_start(session);
 757         ret = lttng_enumerate_process_states(session);
 758         if (ret)
 759                 return ret;
 760         /*
 761          * FIXME
 762          * ret = lttng_enumerate_vm_maps(session);
 763          * if (ret)
 764          *      return ret;
 765          */
 766         ret = lttng_list_interrupts(session);
 767         if (ret)
 768                 return ret;
 769         ret = lttng_enumerate_network_ip_interface(session);
 770         if (ret)
 771                 return ret;
 772         ret = lttng_enumerate_block_devices(session);
 773         switch (ret) {
 774         case 0:
 775                 break;
 776         case -ENOSYS:
 777                 printk(KERN_WARNING "LTTng: block device enumeration is not supported by kernel\n");
 778                 break;
 779         default:
 780                 return ret;
 781         }
 782         ret = lttng_enumerate_cpu_topology(session);
 783         if (ret)
 784                 return ret;
 785
 786         /* TODO lttng_dump_idt_table(session); */
 787         /* TODO lttng_dump_softirq_vec(session); */
 788         /* TODO lttng_list_modules(session); */
 789         /* TODO lttng_dump_swap_files(session); */
 790
 791         /*
 792          * Fire off a work queue on each CPU. Their sole purpose in life
 793          * is to guarantee that each CPU has been in a state where is was in
 794          * syscall mode (i.e. not in a trap, an IRQ or a soft IRQ).
 795          */
 796         lttng_cpus_read_lock();
 797         atomic_set(&kernel_threads_to_run, num_online_cpus());
 798         for_each_online_cpu(cpu) {
 799                 INIT_DELAYED_WORK(&cpu_work[cpu], lttng_statedump_work_func);
 800                 schedule_delayed_work_on(cpu, &cpu_work[cpu], 0);
 801         }
 802         /* Wait for all threads to run */
 803         __wait_event(statedump_wq, (atomic_read(&kernel_threads_to_run) == 0));
 804         lttng_cpus_read_unlock();
 805         /* Our work is done */
 806         trace_lttng_statedump_end(session);
 807         return 0;
 808 }
 809
 810 /*
 811  * Called with session mutex held.
 812  */
 813 int lttng_statedump_start(struct lttng_kernel_session *session)
 814 {
 815         return do_lttng_statedump(session);
 816 }
 817 EXPORT_SYMBOL_GPL(lttng_statedump_start);
 818
 819 static
 820 int __init lttng_statedump_init(void)
 821 {
 822         /*
 823          * Allow module to load even if the fixup cannot be done. This
 824          * will allow seemless transition when the underlying issue fix
 825          * is merged into the Linux kernel, and when tracepoint.c
 826          * "tracepoint_module_notify" is turned into a static function.
 827          */
 828         (void) wrapper_lttng_fixup_sig(THIS_MODULE);
 829         return 0;
 830 }
 831
 832 module_init(lttng_statedump_init);
 833
 834 static
 835 void __exit lttng_statedump_exit(void)
 836 {
 837 }
 838
 839 module_exit(lttng_statedump_exit);
 840
 841 MODULE_LICENSE("GPL and additional rights");
 842 MODULE_AUTHOR("Jean-Hugues Deschenes");
 843 MODULE_DESCRIPTION("LTTng statedump provider");
 844 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
 845         __stringify(LTTNG_MODULES_MINOR_VERSION) "."
 846         __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
 847         LTTNG_MODULES_EXTRAVERSION);