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/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/genhd.h>
  45 #include <wrapper/file.h>
  46 #include <wrapper/fdtable.h>
  47 #include <wrapper/sched.h>
  48
  49 #ifdef CONFIG_LTTNG_HAS_LIST_IRQ
  50 #include <linux/irq.h>
  51 #endif
  52
  53 /* Define the tracepoints, but do not build the probes */
  54 #define CREATE_TRACE_POINTS
  55 #define TRACE_INCLUDE_PATH instrumentation/events/lttng-module
  56 #define TRACE_INCLUDE_FILE lttng-statedump
  57 #define LTTNG_INSTRUMENTATION
  58 #include <instrumentation/events/lttng-module/lttng-statedump.h>
  59
  60 LTTNG_DEFINE_TRACE(lttng_statedump_block_device,
  61         TP_PROTO(struct lttng_session *session,
  62                 dev_t dev, const char *diskname),
  63         TP_ARGS(session, dev, diskname));
  64
  65 LTTNG_DEFINE_TRACE(lttng_statedump_end,
  66         TP_PROTO(struct lttng_session *session),
  67         TP_ARGS(session));
  68
  69 LTTNG_DEFINE_TRACE(lttng_statedump_interrupt,
  70         TP_PROTO(struct lttng_session *session,
  71                 unsigned int irq, const char *chip_name,
  72                 struct irqaction *action),
  73         TP_ARGS(session, irq, chip_name, action));
  74
  75 LTTNG_DEFINE_TRACE(lttng_statedump_file_descriptor,
  76         TP_PROTO(struct lttng_session *session,
  77                 struct files_struct *files,
  78                 int fd, const char *filename,
  79                 unsigned int flags, fmode_t fmode),
  80         TP_ARGS(session, files, fd, filename, flags, fmode));
  81
  82 LTTNG_DEFINE_TRACE(lttng_statedump_start,
  83         TP_PROTO(struct lttng_session *session),
  84         TP_ARGS(session));
  85
  86 LTTNG_DEFINE_TRACE(lttng_statedump_process_state,
  87         TP_PROTO(struct lttng_session *session,
  88                 struct task_struct *p,
  89                 int type, int mode, int submode, int status,
  90                 struct files_struct *files),
  91         TP_ARGS(session, p, type, mode, submode, status, files));
  92
  93 LTTNG_DEFINE_TRACE(lttng_statedump_process_pid_ns,
  94         TP_PROTO(struct lttng_session *session,
  95                 struct task_struct *p,
  96                 struct pid_namespace *pid_ns),
  97         TP_ARGS(session, p, pid_ns));
  98
  99 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,6,0))
 100 LTTNG_DEFINE_TRACE(lttng_statedump_process_cgroup_ns,
 101         TP_PROTO(struct lttng_session *session,
 102                 struct task_struct *p,
 103                 struct cgroup_namespace *cgroup_ns),
 104         TP_ARGS(session, p, cgroup_ns));
 105 #endif
 106
 107 LTTNG_DEFINE_TRACE(lttng_statedump_process_ipc_ns,
 108         TP_PROTO(struct lttng_session *session,
 109                 struct task_struct *p,
 110                 struct ipc_namespace *ipc_ns),
 111         TP_ARGS(session, p, ipc_ns));
 112
 113 #ifndef LTTNG_MNT_NS_MISSING_HEADER
 114 LTTNG_DEFINE_TRACE(lttng_statedump_process_mnt_ns,
 115         TP_PROTO(struct lttng_session *session,
 116                 struct task_struct *p,
 117                 struct mnt_namespace *mnt_ns),
 118         TP_ARGS(session, p, mnt_ns));
 119 #endif
 120
 121 LTTNG_DEFINE_TRACE(lttng_statedump_process_net_ns,
 122         TP_PROTO(struct lttng_session *session,
 123                 struct task_struct *p,
 124                 struct net *net_ns),
 125         TP_ARGS(session, p, net_ns));
 126
 127 LTTNG_DEFINE_TRACE(lttng_statedump_process_user_ns,
 128         TP_PROTO(struct lttng_session *session,
 129                 struct task_struct *p,
 130                 struct user_namespace *user_ns),
 131         TP_ARGS(session, p, user_ns));
 132
 133 LTTNG_DEFINE_TRACE(lttng_statedump_process_uts_ns,
 134         TP_PROTO(struct lttng_session *session,
 135                 struct task_struct *p,
 136                 struct uts_namespace *uts_ns),
 137         TP_ARGS(session, p, uts_ns));
 138
 139 LTTNG_DEFINE_TRACE(lttng_statedump_network_interface,
 140         TP_PROTO(struct lttng_session *session,
 141                 struct net_device *dev, struct in_ifaddr *ifa),
 142         TP_ARGS(session, dev, ifa));
 143
 144 #ifdef LTTNG_HAVE_STATEDUMP_CPU_TOPOLOGY
 145 LTTNG_DEFINE_TRACE(lttng_statedump_cpu_topology,
 146         TP_PROTO(struct lttng_session *session, struct cpuinfo_x86 *c),
 147         TP_ARGS(session, c));
 148 #endif
 149
 150 struct lttng_fd_ctx {
 151         char *page;
 152         struct lttng_session *session;
 153         struct files_struct *files;
 154 };
 155
 156 /*
 157  * Protected by the trace lock.
 158  */
 159 static struct delayed_work cpu_work[NR_CPUS];
 160 static DECLARE_WAIT_QUEUE_HEAD(statedump_wq);
 161 static atomic_t kernel_threads_to_run;
 162
 163 enum lttng_thread_type {
 164         LTTNG_USER_THREAD = 0,
 165         LTTNG_KERNEL_THREAD = 1,
 166 };
 167
 168 enum lttng_execution_mode {
 169         LTTNG_USER_MODE = 0,
 170         LTTNG_SYSCALL = 1,
 171         LTTNG_TRAP = 2,
 172         LTTNG_IRQ = 3,
 173         LTTNG_SOFTIRQ = 4,
 174         LTTNG_MODE_UNKNOWN = 5,
 175 };
 176
 177 enum lttng_execution_submode {
 178         LTTNG_NONE = 0,
 179         LTTNG_UNKNOWN = 1,
 180 };
 181
 182 enum lttng_process_status {
 183         LTTNG_UNNAMED = 0,
 184         LTTNG_WAIT_FORK = 1,
 185         LTTNG_WAIT_CPU = 2,
 186         LTTNG_EXIT = 3,
 187         LTTNG_ZOMBIE = 4,
 188         LTTNG_WAIT = 5,
 189         LTTNG_RUN = 6,
 190         LTTNG_DEAD = 7,
 191 };
 192
 193
 194 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,11,0))
 195
 196 #define LTTNG_PART_STRUCT_TYPE struct block_device
 197
 198 static
 199 int lttng_get_part_name(struct gendisk *disk, struct block_device *part, char *name_buf)
 200 {
 201         const char *p;
 202
 203         p = bdevname(part, name_buf);
 204         if (!p)
 205                 return -ENOSYS;
 206
 207         return 0;
 208 }
 209
 210 static
 211 dev_t lttng_get_part_devt(struct block_device *part)
 212 {
 213         return part->bd_dev;
 214 }
 215
 216 #else
 217
 218 #define LTTNG_PART_STRUCT_TYPE struct hd_struct
 219
 220 static
 221 int lttng_get_part_name(struct gendisk *disk, struct hd_struct *part, char *name_buf)
 222 {
 223         const char *p;
 224         struct block_device bdev;
 225
 226         /*
 227          * Create a partial 'struct blockdevice' to use
 228          * 'bdevname()' which is a simple wrapper over
 229          * 'disk_name()' but has the honor to be EXPORT_SYMBOL.
 230          */
 231         bdev.bd_disk = disk;
 232         bdev.bd_part = part;
 233
 234         p = bdevname(&bdev, name_buf);
 235         if (!p)
 236                 return -ENOSYS;
 237
 238         return 0;
 239 }
 240
 241 static
 242 dev_t lttng_get_part_devt(struct hd_struct *part)
 243 {
 244         return part_devt(part);
 245 }
 246 #endif
 247
 248 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(5,12,0))
 249 static
 250 int lttng_statedump_each_block_device(struct lttng_session *session, struct gendisk *disk)
 251 {
 252         struct block_device *part;
 253         unsigned long idx;
 254         int ret = 0;
 255
 256         /* Include partition 0 */
 257         idx = 0;
 258
 259         rcu_read_lock();
 260         xa_for_each(&disk->part_tbl, idx, part) {
 261                 char name_buf[BDEVNAME_SIZE];
 262
 263                 /* Exclude non-partitions bdev and empty partitions. */
 264                 if (bdev_is_partition(part) && !bdev_nr_sectors(part))
 265                         continue;
 266
 267                 if (lttng_get_part_name(disk, part, name_buf) == -ENOSYS) {
 268                         ret = -ENOSYS;
 269                         goto end;
 270                 }
 271                 trace_lttng_statedump_block_device(session, lttng_get_part_devt(part),
 272                                 name_buf);
 273         }
 274 end:
 275         rcu_read_unlock();
 276         return ret;
 277 }
 278 #else
 279 static
 280 int lttng_statedump_each_block_device(struct lttng_session *session, struct gendisk *disk)
 281 {
 282         struct disk_part_iter piter;
 283         LTTNG_PART_STRUCT_TYPE *part;
 284
 285         disk_part_iter_init(&piter, disk, DISK_PITER_INCL_PART0);
 286
 287         while ((part = disk_part_iter_next(&piter))) {
 288                 char name_buf[BDEVNAME_SIZE];
 289
 290                 if (lttng_get_part_name(disk, part, name_buf) == -ENOSYS) {
 291                         disk_part_iter_exit(&piter);
 292                         return -ENOSYS;
 293                 }
 294                 trace_lttng_statedump_block_device(session, lttng_get_part_devt(part),
 295                                 name_buf);
 296         }
 297         disk_part_iter_exit(&piter);
 298
 299         return 0;
 300 }
 301 #endif
 302
 303 static
 304 int lttng_enumerate_block_devices(struct lttng_session *session)
 305 {
 306         struct class *ptr_block_class;
 307         struct device_type *ptr_disk_type;
 308         struct class_dev_iter iter;
 309         struct device *dev;
 310         int ret = 0;
 311
 312         ptr_block_class = wrapper_get_block_class();
 313         if (!ptr_block_class) {
 314                 ret = -ENOSYS;
 315                 goto end;
 316         }
 317         ptr_disk_type = wrapper_get_disk_type();
 318         if (!ptr_disk_type) {
 319                 ret = -ENOSYS;
 320                 goto end;
 321         }
 322         class_dev_iter_init(&iter, ptr_block_class, NULL, ptr_disk_type);
 323         while ((dev = class_dev_iter_next(&iter))) {
 324                 struct gendisk *disk = dev_to_disk(dev);
 325
 326                 /*
 327                  * Don't show empty devices or things that have been
 328                  * suppressed
 329                  */
 330                 if (get_capacity(disk) == 0 ||
 331                     (disk->flags & LTTNG_GENHD_FL_HIDDEN))
 332                         continue;
 333
 334                 ret = lttng_statedump_each_block_device(session, disk);
 335         }
 336         class_dev_iter_exit(&iter);
 337 end:
 338         return ret;
 339 }
 340
 341 #ifdef CONFIG_INET
 342
 343 static
 344 void lttng_enumerate_device(struct lttng_session *session,
 345                 struct net_device *dev)
 346 {
 347         struct in_device *in_dev;
 348         struct in_ifaddr *ifa;
 349
 350         if (dev->flags & IFF_UP) {
 351                 in_dev = in_dev_get(dev);
 352                 if (in_dev) {
 353                         for (ifa = in_dev->ifa_list; ifa != NULL;
 354                              ifa = ifa->ifa_next) {
 355                                 trace_lttng_statedump_network_interface(
 356                                         session, dev, ifa);
 357                         }
 358                         in_dev_put(in_dev);
 359                 }
 360         } else {
 361                 trace_lttng_statedump_network_interface(
 362                         session, dev, NULL);
 363         }
 364 }
 365
 366 static
 367 int lttng_enumerate_network_ip_interface(struct lttng_session *session)
 368 {
 369         struct net_device *dev;
 370
 371         read_lock(&dev_base_lock);
 372         for_each_netdev(&init_net, dev)
 373                 lttng_enumerate_device(session, dev);
 374         read_unlock(&dev_base_lock);
 375
 376         return 0;
 377 }
 378 #else /* CONFIG_INET */
 379 static inline
 380 int lttng_enumerate_network_ip_interface(struct lttng_session *session)
 381 {
 382         return 0;
 383 }
 384 #endif /* CONFIG_INET */
 385
 386 static
 387 int lttng_dump_one_fd(const void *p, struct file *file, unsigned int fd)
 388 {
 389         const struct lttng_fd_ctx *ctx = p;
 390         const char *s = d_path(&file->f_path, ctx->page, PAGE_SIZE);
 391         unsigned int flags = file->f_flags;
 392         struct fdtable *fdt;
 393
 394         /*
 395          * We don't expose kernel internal flags, only userspace-visible
 396          * flags.
 397          */
 398         flags &= ~FMODE_NONOTIFY;
 399         fdt = files_fdtable(ctx->files);
 400         /*
 401          * We need to check here again whether fd is within the fdt
 402          * max_fds range, because we might be seeing a different
 403          * files_fdtable() than iterate_fd(), assuming only RCU is
 404          * protecting the read. In reality, iterate_fd() holds
 405          * file_lock, which should ensure the fdt does not change while
 406          * the lock is taken, but we are not aware whether this is
 407          * guaranteed or not, so play safe.
 408          */
 409         if (fd < fdt->max_fds && lttng_close_on_exec(fd, fdt))
 410                 flags |= O_CLOEXEC;
 411         if (IS_ERR(s)) {
 412                 struct dentry *dentry = file->f_path.dentry;
 413
 414                 /* Make sure we give at least some info */
 415                 spin_lock(&dentry->d_lock);
 416                 trace_lttng_statedump_file_descriptor(ctx->session,
 417                         ctx->files, fd, dentry->d_name.name, flags,
 418                         file->f_mode);
 419                 spin_unlock(&dentry->d_lock);
 420                 goto end;
 421         }
 422         trace_lttng_statedump_file_descriptor(ctx->session,
 423                 ctx->files, fd, s, flags, file->f_mode);
 424 end:
 425         return 0;
 426 }
 427
 428 /* Called with task lock held. */
 429 static
 430 void lttng_enumerate_files(struct lttng_session *session,
 431                 struct files_struct *files,
 432                 char *tmp)
 433 {
 434         struct lttng_fd_ctx ctx = { .page = tmp, .session = session, .files = files, };
 435
 436         lttng_iterate_fd(files, 0, lttng_dump_one_fd, &ctx);
 437 }
 438
 439 #ifdef LTTNG_HAVE_STATEDUMP_CPU_TOPOLOGY
 440 static
 441 int lttng_enumerate_cpu_topology(struct lttng_session *session)
 442 {
 443         int cpu;
 444         const cpumask_t *cpumask = cpu_possible_mask;
 445
 446         for (cpu = cpumask_first(cpumask); cpu < nr_cpu_ids;
 447                         cpu = cpumask_next(cpu, cpumask)) {
 448                 trace_lttng_statedump_cpu_topology(session, &cpu_data(cpu));
 449         }
 450
 451         return 0;
 452 }
 453 #else
 454 static
 455 int lttng_enumerate_cpu_topology(struct lttng_session *session)
 456 {
 457         return 0;
 458 }
 459 #endif
 460
 461 #if 0
 462 /*
 463  * FIXME: we cannot take a mmap_sem while in a RCU read-side critical section
 464  * (scheduling in atomic). Normally, the tasklist lock protects this kind of
 465  * iteration, but it is not exported to modules.
 466  */
 467 static
 468 void lttng_enumerate_task_vm_maps(struct lttng_session *session,
 469                 struct task_struct *p)
 470 {
 471         struct mm_struct *mm;
 472         struct vm_area_struct *map;
 473         unsigned long ino;
 474
 475         /* get_task_mm does a task_lock... */
 476         mm = get_task_mm(p);
 477         if (!mm)
 478                 return;
 479
 480         map = mm->mmap;
 481         if (map) {
 482                 down_read(&mm->mmap_sem);
 483                 while (map) {
 484                         if (map->vm_file)
 485                                 ino = map->vm_file->lttng_f_dentry->d_inode->i_ino;
 486                         else
 487                                 ino = 0;
 488                         trace_lttng_statedump_vm_map(session, p, map, ino);
 489                         map = map->vm_next;
 490                 }
 491                 up_read(&mm->mmap_sem);
 492         }
 493         mmput(mm);
 494 }
 495
 496 static
 497 int lttng_enumerate_vm_maps(struct lttng_session *session)
 498 {
 499         struct task_struct *p;
 500
 501         rcu_read_lock();
 502         for_each_process(p)
 503                 lttng_enumerate_task_vm_maps(session, p);
 504         rcu_read_unlock();
 505         return 0;
 506 }
 507 #endif
 508
 509 #ifdef CONFIG_LTTNG_HAS_LIST_IRQ
 510
 511 static
 512 int lttng_list_interrupts(struct lttng_session *session)
 513 {
 514         unsigned int irq;
 515         unsigned long flags = 0;
 516         struct irq_desc *desc;
 517
 518 #define irq_to_desc     wrapper_irq_to_desc
 519         /* needs irq_desc */
 520         for_each_irq_desc(irq, desc) {
 521                 struct irqaction *action;
 522                 const char *irq_chip_name =
 523                         irq_desc_get_chip(desc)->name ? : "unnamed_irq_chip";
 524
 525                 local_irq_save(flags);
 526                 raw_spin_lock(&desc->lock);
 527                 for (action = desc->action; action; action = action->next) {
 528                         trace_lttng_statedump_interrupt(session,
 529                                 irq, irq_chip_name, action);
 530                 }
 531                 raw_spin_unlock(&desc->lock);
 532                 local_irq_restore(flags);
 533         }
 534         return 0;
 535 #undef irq_to_desc
 536 }
 537 #else
 538 static inline
 539 int lttng_list_interrupts(struct lttng_session *session)
 540 {
 541         return 0;
 542 }
 543 #endif
 544
 545 /*
 546  * Statedump the task's namespaces using the proc filesystem inode number as
 547  * the unique identifier. The user and pid ns are nested and will be dumped
 548  * recursively.
 549  *
 550  * Called with task lock held.
 551  */
 552 static
 553 void lttng_statedump_process_ns(struct lttng_session *session,
 554                 struct task_struct *p,
 555                 enum lttng_thread_type type,
 556                 enum lttng_execution_mode mode,
 557                 enum lttng_execution_submode submode,
 558                 enum lttng_process_status status)
 559 {
 560         struct nsproxy *proxy;
 561         struct pid_namespace *pid_ns;
 562         struct user_namespace *user_ns;
 563
 564         /*
 565          * The pid and user namespaces are special, they are nested and
 566          * accessed with specific functions instead of the nsproxy struct
 567          * like the other namespaces.
 568          */
 569         pid_ns = task_active_pid_ns(p);
 570         do {
 571                 trace_lttng_statedump_process_pid_ns(session, p, pid_ns);
 572                 pid_ns = pid_ns ? pid_ns->parent : NULL;
 573         } while (pid_ns);
 574
 575
 576         user_ns = task_cred_xxx(p, user_ns);
 577         do {
 578                 trace_lttng_statedump_process_user_ns(session, p, user_ns);
 579                 /*
 580                  * trace_lttng_statedump_process_user_ns() internally
 581                  * checks whether user_ns is NULL. While this does not
 582                  * appear to be a possible return value for
 583                  * task_cred_xxx(), err on the safe side and check
 584                  * for NULL here as well to be consistent with the
 585                  * paranoid behavior of
 586                  * trace_lttng_statedump_process_user_ns().
 587                  */
 588                 user_ns = user_ns ? user_ns->lttng_user_ns_parent : NULL;
 589         } while (user_ns);
 590
 591         /*
 592          * Back and forth on locking strategy within Linux upstream for nsproxy.
 593          * See Linux upstream commit 728dba3a39c66b3d8ac889ddbe38b5b1c264aec3
 594          * "namespaces: Use task_lock and not rcu to protect nsproxy"
 595          * for details.
 596          */
 597 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,17,0) || \
 598                 LTTNG_UBUNTU_KERNEL_RANGE(3,13,11,36, 3,14,0,0) || \
 599                 LTTNG_UBUNTU_KERNEL_RANGE(3,16,1,11, 3,17,0,0) || \
 600                 LTTNG_RHEL_KERNEL_RANGE(3,10,0,229,13,0, 3,11,0,0,0,0))
 601         proxy = p->nsproxy;
 602 #else
 603         rcu_read_lock();
 604         proxy = task_nsproxy(p);
 605 #endif
 606         if (proxy) {
 607 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(4,6,0))
 608                 trace_lttng_statedump_process_cgroup_ns(session, p, proxy->cgroup_ns);
 609 #endif
 610                 trace_lttng_statedump_process_ipc_ns(session, p, proxy->ipc_ns);
 611 #ifndef LTTNG_MNT_NS_MISSING_HEADER
 612                 trace_lttng_statedump_process_mnt_ns(session, p, proxy->mnt_ns);
 613 #endif
 614                 trace_lttng_statedump_process_net_ns(session, p, proxy->net_ns);
 615                 trace_lttng_statedump_process_uts_ns(session, p, proxy->uts_ns);
 616         }
 617 #if (LTTNG_LINUX_VERSION_CODE >= LTTNG_KERNEL_VERSION(3,17,0) || \
 618                 LTTNG_UBUNTU_KERNEL_RANGE(3,13,11,36, 3,14,0,0) || \
 619                 LTTNG_UBUNTU_KERNEL_RANGE(3,16,1,11, 3,17,0,0) || \
 620                 LTTNG_RHEL_KERNEL_RANGE(3,10,0,229,13,0, 3,11,0,0,0,0))
 621         /* (nothing) */
 622 #else
 623         rcu_read_unlock();
 624 #endif
 625 }
 626
 627 static
 628 int lttng_enumerate_process_states(struct lttng_session *session)
 629 {
 630         struct task_struct *g, *p;
 631         char *tmp;
 632
 633         tmp = (char *) __get_free_page(GFP_KERNEL);
 634         if (!tmp)
 635                 return -ENOMEM;
 636
 637         rcu_read_lock();
 638         for_each_process(g) {
 639                 struct files_struct *prev_files = NULL;
 640
 641                 p = g;
 642                 do {
 643                         enum lttng_execution_mode mode =
 644                                 LTTNG_MODE_UNKNOWN;
 645                         enum lttng_execution_submode submode =
 646                                 LTTNG_UNKNOWN;
 647                         enum lttng_process_status status;
 648                         enum lttng_thread_type type;
 649                         struct files_struct *files;
 650
 651                         task_lock(p);
 652                         if (p->exit_state == EXIT_ZOMBIE)
 653                                 status = LTTNG_ZOMBIE;
 654                         else if (p->exit_state == EXIT_DEAD)
 655                                 status = LTTNG_DEAD;
 656                         else if (lttng_task_is_running(p)) {
 657                                 /* Is this a forked child that has not run yet? */
 658                                 if (list_empty(&p->rt.run_list))
 659                                         status = LTTNG_WAIT_FORK;
 660                                 else
 661                                         /*
 662                                          * All tasks are considered as wait_cpu;
 663                                          * the viewer will sort out if the task
 664                                          * was really running at this time.
 665                                          */
 666                                         status = LTTNG_WAIT_CPU;
 667                         } else if (lttng_get_task_state(p) &
 668                                 (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)) {
 669                                 /* Task is waiting for something to complete */
 670                                 status = LTTNG_WAIT;
 671                         } else
 672                                 status = LTTNG_UNNAMED;
 673                         submode = LTTNG_NONE;
 674
 675                         /*
 676                          * Verification of t->mm is to filter out kernel
 677                          * threads; Viewer will further filter out if a
 678                          * user-space thread was in syscall mode or not.
 679                          */
 680                         if (p->mm)
 681                                 type = LTTNG_USER_THREAD;
 682                         else
 683                                 type = LTTNG_KERNEL_THREAD;
 684                         files = p->files;
 685
 686                         trace_lttng_statedump_process_state(session,
 687                                 p, type, mode, submode, status, files);
 688                         lttng_statedump_process_ns(session,
 689                                 p, type, mode, submode, status);
 690                         /*
 691                          * As an optimisation for the common case, do not
 692                          * repeat information for the same files_struct in
 693                          * two consecutive threads. This is the common case
 694                          * for threads sharing the same fd table. RCU guarantees
 695                          * that the same files_struct pointer is not re-used
 696                          * throughout processes/threads iteration.
 697                          */
 698                         if (files && files != prev_files) {
 699                                 lttng_enumerate_files(session, files, tmp);
 700                                 prev_files = files;
 701                         }
 702                         task_unlock(p);
 703                 } while_each_thread(g, p);
 704         }
 705         rcu_read_unlock();
 706
 707         free_page((unsigned long) tmp);
 708
 709         return 0;
 710 }
 711
 712 static
 713 void lttng_statedump_work_func(struct work_struct *work)
 714 {
 715         if (atomic_dec_and_test(&kernel_threads_to_run))
 716                 /* If we are the last thread, wake up do_lttng_statedump */
 717                 wake_up(&statedump_wq);
 718 }
 719
 720 static
 721 int do_lttng_statedump(struct lttng_session *session)
 722 {
 723         int cpu, ret;
 724
 725         trace_lttng_statedump_start(session);
 726         ret = lttng_enumerate_process_states(session);
 727         if (ret)
 728                 return ret;
 729         /*
 730          * FIXME
 731          * ret = lttng_enumerate_vm_maps(session);
 732          * if (ret)
 733          *      return ret;
 734          */
 735         ret = lttng_list_interrupts(session);
 736         if (ret)
 737                 return ret;
 738         ret = lttng_enumerate_network_ip_interface(session);
 739         if (ret)
 740                 return ret;
 741         ret = lttng_enumerate_block_devices(session);
 742         switch (ret) {
 743         case 0:
 744                 break;
 745         case -ENOSYS:
 746                 printk(KERN_WARNING "LTTng: block device enumeration is not supported by kernel\n");
 747                 break;
 748         default:
 749                 return ret;
 750         }
 751         ret = lttng_enumerate_cpu_topology(session);
 752         if (ret)
 753                 return ret;
 754
 755         /* TODO lttng_dump_idt_table(session); */
 756         /* TODO lttng_dump_softirq_vec(session); */
 757         /* TODO lttng_list_modules(session); */
 758         /* TODO lttng_dump_swap_files(session); */
 759
 760         /*
 761          * Fire off a work queue on each CPU. Their sole purpose in life
 762          * is to guarantee that each CPU has been in a state where is was in
 763          * syscall mode (i.e. not in a trap, an IRQ or a soft IRQ).
 764          */
 765         lttng_cpus_read_lock();
 766         atomic_set(&kernel_threads_to_run, num_online_cpus());
 767         for_each_online_cpu(cpu) {
 768                 INIT_DELAYED_WORK(&cpu_work[cpu], lttng_statedump_work_func);
 769                 schedule_delayed_work_on(cpu, &cpu_work[cpu], 0);
 770         }
 771         /* Wait for all threads to run */
 772         __wait_event(statedump_wq, (atomic_read(&kernel_threads_to_run) == 0));
 773         lttng_cpus_read_unlock();
 774         /* Our work is done */
 775         trace_lttng_statedump_end(session);
 776         return 0;
 777 }
 778
 779 /*
 780  * Called with session mutex held.
 781  */
 782 int lttng_statedump_start(struct lttng_session *session)
 783 {
 784         return do_lttng_statedump(session);
 785 }
 786 EXPORT_SYMBOL_GPL(lttng_statedump_start);
 787
 788 static
 789 int __init lttng_statedump_init(void)
 790 {
 791         /*
 792          * Allow module to load even if the fixup cannot be done. This
 793          * will allow seemless transition when the underlying issue fix
 794          * is merged into the Linux kernel, and when tracepoint.c
 795          * "tracepoint_module_notify" is turned into a static function.
 796          */
 797         (void) wrapper_lttng_fixup_sig(THIS_MODULE);
 798         return 0;
 799 }
 800
 801 module_init(lttng_statedump_init);
 802
 803 static
 804 void __exit lttng_statedump_exit(void)
 805 {
 806 }
 807
 808 module_exit(lttng_statedump_exit);
 809
 810 MODULE_LICENSE("GPL and additional rights");
 811 MODULE_AUTHOR("Jean-Hugues Deschenes");
 812 MODULE_DESCRIPTION("LTTng statedump provider");
 813 MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
 814         __stringify(LTTNG_MODULES_MINOR_VERSION) "."
 815         __stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
 816         LTTNG_MODULES_EXTRAVERSION);