arch/x86/kernel/dumpstack_32.c

   1 /*
   2  *  Copyright (C) 1991, 1992  Linus Torvalds
   3  *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
   4  */
   5 #include <linux/kallsyms.h>
   6 #include <linux/kprobes.h>
   7 #include <linux/uaccess.h>
   8 #include <linux/utsname.h>
   9 #include <linux/hardirq.h>
  10 #include <linux/kdebug.h>
  11 #include <linux/module.h>
  12 #include <linux/ptrace.h>
  13 #include <linux/kexec.h>
  14 #include <linux/bug.h>
  15 #include <linux/nmi.h>
  16
  17 #include <asm/stacktrace.h>
  18
  19 int panic_on_unrecovered_nmi;
  20 int kstack_depth_to_print = 24;
  21 static unsigned int code_bytes = 64;
  22 static int die_counter;
  23
  24 void printk_address(unsigned long address, int reliable)
  25 {
  26 #ifdef CONFIG_KALLSYMS
  27         unsigned long offset = 0;
  28         unsigned long symsize;
  29         const char *symname;
  30         char *modname;
  31         char *delim = ":";
  32         char namebuf[KSYM_NAME_LEN];
  33         char reliab[4] = "";
  34
  35         symname = kallsyms_lookup(address, &symsize, &offset,
  36                                         &modname, namebuf);
  37         if (!symname) {
  38                 printk(" [<%08lx>]\n", address);
  39                 return;
  40         }
  41         if (!reliable)
  42                 strcpy(reliab, "? ");
  43
  44         if (!modname)
  45                 modname = delim = "";
  46         printk(" [<%08lx>] %s%s%s%s%s+0x%lx/0x%lx\n",
  47                 address, reliab, delim, modname, delim, symname, offset, symsize);
  48 #else
  49         printk(" [<%08lx>]\n", address);
  50 #endif
  51 }
  52
  53 static inline int valid_stack_ptr(struct thread_info *tinfo,
  54                         void *p, unsigned int size)
  55 {
  56         void *t = tinfo;
  57         return  p > t && p <= t + THREAD_SIZE - size;
  58 }
  59
  60 /* The form of the top of the frame on the stack */
  61 struct stack_frame {
  62         struct stack_frame *next_frame;
  63         unsigned long return_address;
  64 };
  65
  66 static inline unsigned long
  67 print_context_stack(struct thread_info *tinfo,
  68                 unsigned long *stack, unsigned long bp,
  69                 const struct stacktrace_ops *ops, void *data)
  70 {
  71         struct stack_frame *frame = (struct stack_frame *)bp;
  72
  73         while (valid_stack_ptr(tinfo, stack, sizeof(*stack))) {
  74                 unsigned long addr;
  75
  76                 addr = *stack;
  77                 if (__kernel_text_address(addr)) {
  78                         if ((unsigned long) stack == bp + 4) {
  79                                 ops->address(data, addr, 1);
  80                                 frame = frame->next_frame;
  81                                 bp = (unsigned long) frame;
  82                         } else {
  83                                 ops->address(data, addr, bp == 0);
  84                         }
  85                 }
  86                 stack++;
  87         }
  88         return bp;
  89 }
  90
  91 void dump_trace(struct task_struct *task, struct pt_regs *regs,
  92                 unsigned long *stack, unsigned long bp,
  93                 const struct stacktrace_ops *ops, void *data)
  94 {
  95         if (!task)
  96                 task = current;
  97
  98         if (!stack) {
  99                 unsigned long dummy;
 100                 stack = &dummy;
 101                 if (task != current)
 102                         stack = (unsigned long *)task->thread.sp;
 103         }
 104
 105 #ifdef CONFIG_FRAME_POINTER
 106         if (!bp) {
 107                 if (task == current) {
 108                         /* Grab bp right from our regs */
 109                         asm("movl %%ebp, %0" : "=r" (bp) :);
 110                 } else {
 111                         /* bp is the last reg pushed by switch_to */
 112                         bp = *(unsigned long *) task->thread.sp;
 113                 }
 114         }
 115 #endif
 116
 117         for (;;) {
 118                 struct thread_info *context;
 119
 120                 context = (struct thread_info *)
 121                         ((unsigned long)stack & (~(THREAD_SIZE - 1)));
 122                 bp = print_context_stack(context, stack, bp, ops, data);
 123                 /*
 124                  * Should be after the line below, but somewhere
 125                  * in early boot context comes out corrupted and we
 126                  * can't reference it:
 127                  */
 128                 if (ops->stack(data, "IRQ") < 0)
 129                         break;
 130                 stack = (unsigned long *)context->previous_esp;
 131                 if (!stack)
 132                         break;
 133                 touch_nmi_watchdog();
 134         }
 135 }
 136 EXPORT_SYMBOL(dump_trace);
 137
 138 static void
 139 print_trace_warning_symbol(void *data, char *msg, unsigned long symbol)
 140 {
 141         printk(data);
 142         print_symbol(msg, symbol);
 143         printk("\n");
 144 }
 145
 146 static void print_trace_warning(void *data, char *msg)
 147 {
 148         printk("%s%s\n", (char *)data, msg);
 149 }
 150
 151 static int print_trace_stack(void *data, char *name)
 152 {
 153         return 0;
 154 }
 155
 156 /*
 157  * Print one address/symbol entries per line.
 158  */
 159 static void print_trace_address(void *data, unsigned long addr, int reliable)
 160 {
 161         printk("%s [<%08lx>] ", (char *)data, addr);
 162         if (!reliable)
 163                 printk("? ");
 164         print_symbol("%s\n", addr);
 165         touch_nmi_watchdog();
 166 }
 167
 168 static const struct stacktrace_ops print_trace_ops = {
 169         .warning = print_trace_warning,
 170         .warning_symbol = print_trace_warning_symbol,
 171         .stack = print_trace_stack,
 172         .address = print_trace_address,
 173 };
 174
 175 static void
 176 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs,
 177                 unsigned long *stack, unsigned long bp, char *log_lvl)
 178 {
 179         dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl);
 180         printk("%s =======================\n", log_lvl);
 181 }
 182
 183 void show_trace(struct task_struct *task, struct pt_regs *regs,
 184                 unsigned long *stack, unsigned long bp)
 185 {
 186         show_trace_log_lvl(task, regs, stack, bp, "");
 187 }
 188
 189 static void
 190 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 191                    unsigned long *sp, unsigned long bp, char *log_lvl)
 192 {
 193         unsigned long *stack;
 194         int i;
 195
 196         if (sp == NULL) {
 197                 if (task)
 198                         sp = (unsigned long *)task->thread.sp;
 199                 else
 200                         sp = (unsigned long *)&sp;
 201         }
 202
 203         stack = sp;
 204         for (i = 0; i < kstack_depth_to_print; i++) {
 205                 if (kstack_end(stack))
 206                         break;
 207                 if (i && ((i % 8) == 0))
 208                         printk("\n%s       ", log_lvl);
 209                 printk("%08lx ", *stack++);
 210         }
 211         printk("\n%sCall Trace:\n", log_lvl);
 212
 213         show_trace_log_lvl(task, regs, sp, bp, log_lvl);
 214 }
 215
 216 void show_stack(struct task_struct *task, unsigned long *sp)
 217 {
 218         printk("       ");
 219         show_stack_log_lvl(task, NULL, sp, 0, "");
 220 }
 221
 222 /*
 223  * The architecture-independent dump_stack generator
 224  */
 225 void dump_stack(void)
 226 {
 227         unsigned long bp = 0;
 228         unsigned long stack;
 229
 230 #ifdef CONFIG_FRAME_POINTER
 231         if (!bp)
 232                 asm("movl %%ebp, %0" : "=r" (bp):);
 233 #endif
 234
 235         printk("Pid: %d, comm: %.20s %s %s %.*s\n",
 236                 current->pid, current->comm, print_tainted(),
 237                 init_utsname()->release,
 238                 (int)strcspn(init_utsname()->version, " "),
 239                 init_utsname()->version);
 240
 241         show_trace(current, NULL, &stack, bp);
 242 }
 243
 244 EXPORT_SYMBOL(dump_stack);
 245
 246 void show_registers(struct pt_regs *regs)
 247 {
 248         int i;
 249
 250         print_modules();
 251         __show_regs(regs, 0);
 252
 253         printk(KERN_EMERG "Process %.*s (pid: %d, ti=%p task=%p task.ti=%p)",
 254                 TASK_COMM_LEN, current->comm, task_pid_nr(current),
 255                 current_thread_info(), current, task_thread_info(current));
 256         /*
 257          * When in-kernel, we also print out the stack and code at the
 258          * time of the fault..
 259          */
 260         if (!user_mode_vm(regs)) {
 261                 unsigned int code_prologue = code_bytes * 43 / 64;
 262                 unsigned int code_len = code_bytes;
 263                 unsigned char c;
 264                 u8 *ip;
 265
 266                 printk("\n" KERN_EMERG "Stack: ");
 267                 show_stack_log_lvl(NULL, regs, &regs->sp, 0, KERN_EMERG);
 268
 269                 printk(KERN_EMERG "Code: ");
 270
 271                 ip = (u8 *)regs->ip - code_prologue;
 272                 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
 273                         /* try starting at EIP */
 274                         ip = (u8 *)regs->ip;
 275                         code_len = code_len - code_prologue + 1;
 276                 }
 277                 for (i = 0; i < code_len; i++, ip++) {
 278                         if (ip < (u8 *)PAGE_OFFSET ||
 279                                         probe_kernel_address(ip, c)) {
 280                                 printk(" Bad EIP value.");
 281                                 break;
 282                         }
 283                         if (ip == (u8 *)regs->ip)
 284                                 printk("<%02x> ", c);
 285                         else
 286                                 printk("%02x ", c);
 287                 }
 288         }
 289         printk("\n");
 290 }
 291
 292 int is_valid_bugaddr(unsigned long ip)
 293 {
 294         unsigned short ud2;
 295
 296         if (ip < PAGE_OFFSET)
 297                 return 0;
 298         if (probe_kernel_address((unsigned short *)ip, ud2))
 299                 return 0;
 300
 301         return ud2 == 0x0b0f;
 302 }
 303
 304 static raw_spinlock_t die_lock = __RAW_SPIN_LOCK_UNLOCKED;
 305 static int die_owner = -1;
 306 static unsigned int die_nest_count;
 307
 308 unsigned __kprobes long oops_begin(void)
 309 {
 310         unsigned long flags;
 311
 312         oops_enter();
 313
 314         if (die_owner != raw_smp_processor_id()) {
 315                 console_verbose();
 316                 raw_local_irq_save(flags);
 317                 __raw_spin_lock(&die_lock);
 318                 die_owner = smp_processor_id();
 319                 die_nest_count = 0;
 320                 bust_spinlocks(1);
 321         } else {
 322                 raw_local_irq_save(flags);
 323         }
 324         die_nest_count++;
 325         return flags;
 326 }
 327
 328 void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr)
 329 {
 330         bust_spinlocks(0);
 331         die_owner = -1;
 332         add_taint(TAINT_DIE);
 333         __raw_spin_unlock(&die_lock);
 334         raw_local_irq_restore(flags);
 335
 336         if (!regs)
 337                 return;
 338
 339         if (kexec_should_crash(current))
 340                 crash_kexec(regs);
 341
 342         if (in_interrupt())
 343                 panic("Fatal exception in interrupt");
 344
 345         if (panic_on_oops)
 346                 panic("Fatal exception");
 347
 348         oops_exit();
 349         do_exit(signr);
 350 }
 351
 352 int __kprobes __die(const char *str, struct pt_regs *regs, long err)
 353 {
 354         unsigned short ss;
 355         unsigned long sp;
 356
 357         printk(KERN_EMERG "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter);
 358 #ifdef CONFIG_PREEMPT
 359         printk("PREEMPT ");
 360 #endif
 361 #ifdef CONFIG_SMP
 362         printk("SMP ");
 363 #endif
 364 #ifdef CONFIG_DEBUG_PAGEALLOC
 365         printk("DEBUG_PAGEALLOC");
 366 #endif
 367         printk("\n");
 368         if (notify_die(DIE_OOPS, str, regs, err,
 369                         current->thread.trap_no, SIGSEGV) == NOTIFY_STOP)
 370                 return 1;
 371
 372         show_registers(regs);
 373         /* Executive summary in case the oops scrolled away */
 374         sp = (unsigned long) (&regs->sp);
 375         savesegment(ss, ss);
 376         if (user_mode(regs)) {
 377                 sp = regs->sp;
 378                 ss = regs->ss & 0xffff;
 379         }
 380         printk(KERN_EMERG "EIP: [<%08lx>] ", regs->ip);
 381         print_symbol("%s", regs->ip);
 382         printk(" SS:ESP %04x:%08lx\n", ss, sp);
 383         return 0;
 384 }
 385
 386 /*
 387  * This is gone through when something in the kernel has done something bad
 388  * and is about to be terminated:
 389  */
 390 void die(const char *str, struct pt_regs *regs, long err)
 391 {
 392         unsigned long flags = oops_begin();
 393
 394         if (die_nest_count < 3) {
 395                 report_bug(regs->ip, regs);
 396
 397                 if (__die(str, regs, err))
 398                         regs = NULL;
 399         } else {
 400                 printk(KERN_EMERG "Recursive die() failure, output suppressed\n");
 401         }
 402
 403         oops_end(flags, regs, SIGSEGV);
 404 }
 405
 406 static DEFINE_SPINLOCK(nmi_print_lock);
 407
 408 void notrace __kprobes
 409 die_nmi(char *str, struct pt_regs *regs, int do_panic)
 410 {
 411         if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP)
 412                 return;
 413
 414         spin_lock(&nmi_print_lock);
 415         /*
 416         * We are in trouble anyway, lets at least try
 417         * to get a message out:
 418         */
 419         bust_spinlocks(1);
 420         printk(KERN_EMERG "%s", str);
 421         printk(" on CPU%d, ip %08lx, registers:\n",
 422                 smp_processor_id(), regs->ip);
 423         show_registers(regs);
 424         if (do_panic)
 425                 panic("Non maskable interrupt");
 426         console_silent();
 427         spin_unlock(&nmi_print_lock);
 428         bust_spinlocks(0);
 429
 430         /*
 431          * If we are in kernel we are probably nested up pretty bad
 432          * and might aswell get out now while we still can:
 433          */
 434         if (!user_mode_vm(regs)) {
 435                 current->thread.trap_no = 2;
 436                 crash_kexec(regs);
 437         }
 438
 439         do_exit(SIGSEGV);
 440 }
 441
 442 static int __init kstack_setup(char *s)
 443 {
 444         kstack_depth_to_print = simple_strtoul(s, NULL, 0);
 445
 446         return 1;
 447 }
 448 __setup("kstack=", kstack_setup);
 449
 450 static int __init code_bytes_setup(char *s)
 451 {
 452         code_bytes = simple_strtoul(s, NULL, 0);
 453         if (code_bytes > 8192)
 454                 code_bytes = 8192;
 455
 456         return 1;
 457 }
 458 __setup("code_bytes=", code_bytes_setup);