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