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