lttng-statedump-impl.c

   1 /*
   2  * lttng-statedump.c
   3  *
   4  * Linux Trace Toolkit Next Generation Kernel State Dump
   5  *
   6  * Copyright 2005 Jean-Hugues Deschenes <jean-hugues.deschenes@polymtl.ca>
   7  * Copyright 2006-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
   8  *
   9  * This library is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; only
  12  * version 2.1 of the License.
  13  *
  14  * This library is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with this library; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  *
  23  * Changes:
  24  *      Eric Clement:                   Add listing of network IP interface
  25  *      2006, 2007 Mathieu Desnoyers    Fix kernel threads
  26  *                                      Various updates
  27  */
  28
  29 #include <linux/init.h>
  30 #include <linux/module.h>
  31 #include <linux/netlink.h>
  32 #include <linux/inet.h>
  33 #include <linux/ip.h>
  34 #include <linux/kthread.h>
  35 #include <linux/proc_fs.h>
  36 #include <linux/file.h>
  37 #include <linux/interrupt.h>
  38 #include <linux/irqnr.h>
  39 #include <linux/cpu.h>
  40 #include <linux/netdevice.h>
  41 #include <linux/inetdevice.h>
  42 #include <linux/sched.h>
  43 #include <linux/mm.h>
  44 #include <linux/fdtable.h>
  45 #include <linux/swap.h>
  46 #include <linux/wait.h>
  47 #include <linux/mutex.h>
  48
  49 #include "lttng-events.h"
  50 #include "wrapper/irqdesc.h"
  51 #include "wrapper/spinlock.h"
  52 #include "wrapper/fdtable.h"
  53
  54 #ifdef CONFIG_GENERIC_HARDIRQS
  55 #include <linux/irq.h>
  56 #endif
  57
  58 /* Define the tracepoints, but do not build the probes */
  59 #define CREATE_TRACE_POINTS
  60 #define TRACE_INCLUDE_PATH ../instrumentation/events/lttng-module
  61 #define TRACE_INCLUDE_FILE lttng-statedump
  62 #include "instrumentation/events/lttng-module/lttng-statedump.h"
  63
  64 struct lttng_fd_ctx {
  65         char *page;
  66         struct lttng_session *session;
  67         struct task_struct *p;
  68 };
  69
  70 /*
  71  * Protected by the trace lock.
  72  */
  73 static struct delayed_work cpu_work[NR_CPUS];
  74 static DECLARE_WAIT_QUEUE_HEAD(statedump_wq);
  75 static atomic_t kernel_threads_to_run;
  76
  77 enum lttng_thread_type {
  78         LTTNG_USER_THREAD = 0,
  79         LTTNG_KERNEL_THREAD = 1,
  80 };
  81
  82 enum lttng_execution_mode {
  83         LTTNG_USER_MODE = 0,
  84         LTTNG_SYSCALL = 1,
  85         LTTNG_TRAP = 2,
  86         LTTNG_IRQ = 3,
  87         LTTNG_SOFTIRQ = 4,
  88         LTTNG_MODE_UNKNOWN = 5,
  89 };
  90
  91 enum lttng_execution_submode {
  92         LTTNG_NONE = 0,
  93         LTTNG_UNKNOWN = 1,
  94 };
  95
  96 enum lttng_process_status {
  97         LTTNG_UNNAMED = 0,
  98         LTTNG_WAIT_FORK = 1,
  99         LTTNG_WAIT_CPU = 2,
 100         LTTNG_EXIT = 3,
 101         LTTNG_ZOMBIE = 4,
 102         LTTNG_WAIT = 5,
 103         LTTNG_RUN = 6,
 104         LTTNG_DEAD = 7,
 105 };
 106
 107 #ifdef CONFIG_INET
 108 static
 109 void lttng_enumerate_device(struct lttng_session *session,
 110                 struct net_device *dev)
 111 {
 112         struct in_device *in_dev;
 113         struct in_ifaddr *ifa;
 114
 115         if (dev->flags & IFF_UP) {
 116                 in_dev = in_dev_get(dev);
 117                 if (in_dev) {
 118                         for (ifa = in_dev->ifa_list; ifa != NULL;
 119                              ifa = ifa->ifa_next) {
 120                                 trace_lttng_statedump_network_interface(
 121                                         session, dev, ifa);
 122                         }
 123                         in_dev_put(in_dev);
 124                 }
 125         } else {
 126                 trace_lttng_statedump_network_interface(
 127                         session, dev, NULL);
 128         }
 129 }
 130
 131 static
 132 int lttng_enumerate_network_ip_interface(struct lttng_session *session)
 133 {
 134         struct net_device *dev;
 135
 136         read_lock(&dev_base_lock);
 137         for_each_netdev(&init_net, dev)
 138                 lttng_enumerate_device(session, dev);
 139         read_unlock(&dev_base_lock);
 140
 141         return 0;
 142 }
 143 #else /* CONFIG_INET */
 144 static inline
 145 int lttng_enumerate_network_ip_interface(struct lttng_session *session)
 146 {
 147         return 0;
 148 }
 149 #endif /* CONFIG_INET */
 150
 151 static
 152 int lttng_dump_one_fd(const void *p, struct file *file, unsigned int fd)
 153 {
 154         const struct lttng_fd_ctx *ctx = p;
 155         const char *s = d_path(&file->f_path, ctx->page, PAGE_SIZE);
 156
 157         if (IS_ERR(s)) {
 158                 struct dentry *dentry = file->f_path.dentry;
 159
 160                 /* Make sure we give at least some info */
 161                 spin_lock(&dentry->d_lock);
 162                 trace_lttng_statedump_file_descriptor(ctx->session, ctx->p, fd,
 163                         dentry->d_name.name);
 164                 spin_unlock(&dentry->d_lock);
 165                 goto end;
 166         }
 167         trace_lttng_statedump_file_descriptor(ctx->session, ctx->p, fd, s);
 168 end:
 169         return 0;
 170 }
 171
 172 static
 173 void lttng_enumerate_task_fd(struct lttng_session *session,
 174                 struct task_struct *p, char *tmp)
 175 {
 176         struct lttng_fd_ctx ctx = { .page = tmp, .session = session, .p = p };
 177
 178         task_lock(p);
 179         lttng_iterate_fd(p->files, 0, lttng_dump_one_fd, &ctx);
 180         task_unlock(p);
 181 }
 182
 183 static
 184 int lttng_enumerate_file_descriptors(struct lttng_session *session)
 185 {
 186         struct task_struct *p;
 187         char *tmp = (char *) __get_free_page(GFP_KERNEL);
 188
 189         /* Enumerate active file descriptors */
 190         rcu_read_lock();
 191         for_each_process(p)
 192                 lttng_enumerate_task_fd(session, p, tmp);
 193         rcu_read_unlock();
 194         free_page((unsigned long) tmp);
 195         return 0;
 196 }
 197
 198 #if 0
 199 /*
 200  * FIXME: we cannot take a mmap_sem while in a RCU read-side critical section
 201  * (scheduling in atomic). Normally, the tasklist lock protects this kind of
 202  * iteration, but it is not exported to modules.
 203  */
 204 static
 205 void lttng_enumerate_task_vm_maps(struct lttng_session *session,
 206                 struct task_struct *p)
 207 {
 208         struct mm_struct *mm;
 209         struct vm_area_struct *map;
 210         unsigned long ino;
 211
 212         /* get_task_mm does a task_lock... */
 213         mm = get_task_mm(p);
 214         if (!mm)
 215                 return;
 216
 217         map = mm->mmap;
 218         if (map) {
 219                 down_read(&mm->mmap_sem);
 220                 while (map) {
 221                         if (map->vm_file)
 222                                 ino = map->vm_file->f_dentry->d_inode->i_ino;
 223                         else
 224                                 ino = 0;
 225                         trace_lttng_statedump_vm_map(session, p, map, ino);
 226                         map = map->vm_next;
 227                 }
 228                 up_read(&mm->mmap_sem);
 229         }
 230         mmput(mm);
 231 }
 232
 233 static
 234 int lttng_enumerate_vm_maps(struct lttng_session *session)
 235 {
 236         struct task_struct *p;
 237
 238         rcu_read_lock();
 239         for_each_process(p)
 240                 lttng_enumerate_task_vm_maps(session, p);
 241         rcu_read_unlock();
 242         return 0;
 243 }
 244 #endif
 245
 246 #ifdef CONFIG_GENERIC_HARDIRQS
 247
 248 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,39))
 249 #define irq_desc_get_chip(desc) get_irq_desc_chip(desc)
 250 #endif
 251
 252 static
 253 void lttng_list_interrupts(struct lttng_session *session)
 254 {
 255         unsigned int irq;
 256         unsigned long flags = 0;
 257         struct irq_desc *desc;
 258
 259 #define irq_to_desc     wrapper_irq_to_desc
 260         /* needs irq_desc */
 261         for_each_irq_desc(irq, desc) {
 262                 struct irqaction *action;
 263                 const char *irq_chip_name =
 264                         irq_desc_get_chip(desc)->name ? : "unnamed_irq_chip";
 265
 266                 local_irq_save(flags);
 267                 wrapper_desc_spin_lock(&desc->lock);
 268                 for (action = desc->action; action; action = action->next) {
 269                         trace_lttng_statedump_interrupt(session,
 270                                 irq, irq_chip_name, action);
 271                 }
 272                 wrapper_desc_spin_unlock(&desc->lock);
 273                 local_irq_restore(flags);
 274         }
 275 #undef irq_to_desc
 276 }
 277 #else
 278 static inline
 279 void list_interrupts(struct lttng_session *session)
 280 {
 281 }
 282 #endif
 283
 284 static
 285 void lttng_statedump_process_ns(struct lttng_session *session,
 286                 struct task_struct *p,
 287                 enum lttng_thread_type type,
 288                 enum lttng_execution_mode mode,
 289                 enum lttng_execution_submode submode,
 290                 enum lttng_process_status status)
 291 {
 292         struct nsproxy *proxy;
 293         struct pid_namespace *pid_ns;
 294
 295         rcu_read_lock();
 296         proxy = task_nsproxy(p);
 297         if (proxy) {
 298                 pid_ns = proxy->pid_ns;
 299                 do {
 300                         trace_lttng_statedump_process_state(session,
 301                                 p, type, mode, submode, status, pid_ns);
 302                         pid_ns = pid_ns->parent;
 303                 } while (pid_ns);
 304         } else {
 305                 trace_lttng_statedump_process_state(session,
 306                         p, type, mode, submode, status, NULL);
 307         }
 308         rcu_read_unlock();
 309 }
 310
 311 static
 312 int lttng_enumerate_process_states(struct lttng_session *session)
 313 {
 314         struct task_struct *g, *p;
 315
 316         rcu_read_lock();
 317         for_each_process(g) {
 318                 p = g;
 319                 do {
 320                         enum lttng_execution_mode mode =
 321                                 LTTNG_MODE_UNKNOWN;
 322                         enum lttng_execution_submode submode =
 323                                 LTTNG_UNKNOWN;
 324                         enum lttng_process_status status;
 325                         enum lttng_thread_type type;
 326
 327                         task_lock(p);
 328                         if (p->exit_state == EXIT_ZOMBIE)
 329                                 status = LTTNG_ZOMBIE;
 330                         else if (p->exit_state == EXIT_DEAD)
 331                                 status = LTTNG_DEAD;
 332                         else if (p->state == TASK_RUNNING) {
 333                                 /* Is this a forked child that has not run yet? */
 334                                 if (list_empty(&p->rt.run_list))
 335                                         status = LTTNG_WAIT_FORK;
 336                                 else
 337                                         /*
 338                                          * All tasks are considered as wait_cpu;
 339                                          * the viewer will sort out if the task
 340                                          * was really running at this time.
 341                                          */
 342                                         status = LTTNG_WAIT_CPU;
 343                         } else if (p->state &
 344                                 (TASK_INTERRUPTIBLE | TASK_UNINTERRUPTIBLE)) {
 345                                 /* Task is waiting for something to complete */
 346                                 status = LTTNG_WAIT;
 347                         } else
 348                                 status = LTTNG_UNNAMED;
 349                         submode = LTTNG_NONE;
 350
 351                         /*
 352                          * Verification of t->mm is to filter out kernel
 353                          * threads; Viewer will further filter out if a
 354                          * user-space thread was in syscall mode or not.
 355                          */
 356                         if (p->mm)
 357                                 type = LTTNG_USER_THREAD;
 358                         else
 359                                 type = LTTNG_KERNEL_THREAD;
 360                         lttng_statedump_process_ns(session,
 361                                 p, type, mode, submode, status);
 362                         task_unlock(p);
 363                 } while_each_thread(g, p);
 364         }
 365         rcu_read_unlock();
 366
 367         return 0;
 368 }
 369
 370 static
 371 void lttng_statedump_work_func(struct work_struct *work)
 372 {
 373         if (atomic_dec_and_test(&kernel_threads_to_run))
 374                 /* If we are the last thread, wake up do_lttng_statedump */
 375                 wake_up(&statedump_wq);
 376 }
 377
 378 static
 379 int do_lttng_statedump(struct lttng_session *session)
 380 {
 381         int cpu;
 382
 383         printk(KERN_DEBUG "LTT state dump thread start\n");
 384         trace_lttng_statedump_start(session);
 385         lttng_enumerate_process_states(session);
 386         lttng_enumerate_file_descriptors(session);
 387         /* FIXME lttng_enumerate_vm_maps(session); */
 388         lttng_list_interrupts(session);
 389         lttng_enumerate_network_ip_interface(session);
 390
 391         /* TODO lttng_dump_idt_table(session); */
 392         /* TODO lttng_dump_softirq_vec(session); */
 393         /* TODO lttng_list_modules(session); */
 394         /* TODO lttng_dump_swap_files(session); */
 395
 396         /*
 397          * Fire off a work queue on each CPU. Their sole purpose in life
 398          * is to guarantee that each CPU has been in a state where is was in
 399          * syscall mode (i.e. not in a trap, an IRQ or a soft IRQ).
 400          */
 401         get_online_cpus();
 402         atomic_set(&kernel_threads_to_run, num_online_cpus());
 403         for_each_online_cpu(cpu) {
 404                 INIT_DELAYED_WORK(&cpu_work[cpu], lttng_statedump_work_func);
 405                 schedule_delayed_work_on(cpu, &cpu_work[cpu], 0);
 406         }
 407         /* Wait for all threads to run */
 408         __wait_event(statedump_wq, (atomic_read(&kernel_threads_to_run) == 0));
 409         put_online_cpus();
 410         /* Our work is done */
 411         printk(KERN_DEBUG "LTT state dump end\n");
 412         trace_lttng_statedump_end(session);
 413         return 0;
 414 }
 415
 416 /*
 417  * Called with session mutex held.
 418  */
 419 int lttng_statedump_start(struct lttng_session *session)
 420 {
 421         printk(KERN_DEBUG "LTTng: state dump begin\n");
 422         return do_lttng_statedump(session);
 423 }
 424 EXPORT_SYMBOL_GPL(lttng_statedump_start);
 425
 426 MODULE_LICENSE("GPL and additional rights");
 427 MODULE_AUTHOR("Jean-Hugues Deschenes");
 428 MODULE_DESCRIPTION("Linux Trace Toolkit Next Generation Statedump");