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