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