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