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