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 4 21 #define get_bp(bp) asm("movq %%rbp, %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 unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, 35 unsigned *usedp, char **idp) 36 { 37 static char ids[][8] = { 38 [DEBUG_STACK - 1] = "#DB", 39 [NMI_STACK - 1] = "NMI", 40 [DOUBLEFAULT_STACK - 1] = "#DF", 41 [STACKFAULT_STACK - 1] = "#SS", 42 [MCE_STACK - 1] = "#MC", 43 #if DEBUG_STKSZ > EXCEPTION_STKSZ 44 [N_EXCEPTION_STACKS ... 45 N_EXCEPTION_STACKS + DEBUG_STKSZ / EXCEPTION_STKSZ - 2] = "#DB[?]" 46 #endif 47 }; 48 unsigned k; 49 50 /* 51 * Iterate over all exception stacks, and figure out whether 52 * 'stack' is in one of them: 53 */ 54 for (k = 0; k < N_EXCEPTION_STACKS; k++) { 55 unsigned long end = per_cpu(orig_ist, cpu).ist[k]; 56 /* 57 * Is 'stack' above this exception frame's end? 58 * If yes then skip to the next frame. 59 */ 60 if (stack >= end) 61 continue; 62 /* 63 * Is 'stack' above this exception frame's start address? 64 * If yes then we found the right frame. 65 */ 66 if (stack >= end - EXCEPTION_STKSZ) { 67 /* 68 * Make sure we only iterate through an exception 69 * stack once. If it comes up for the second time 70 * then there's something wrong going on - just 71 * break out and return NULL: 72 */ 73 if (*usedp & (1U << k)) 74 break; 75 *usedp |= 1U << k; 76 *idp = ids[k]; 77 return (unsigned long *)end; 78 } 79 /* 80 * If this is a debug stack, and if it has a larger size than 81 * the usual exception stacks, then 'stack' might still 82 * be within the lower portion of the debug stack: 83 */ 84 #if DEBUG_STKSZ > EXCEPTION_STKSZ 85 if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) { 86 unsigned j = N_EXCEPTION_STACKS - 1; 87 88 /* 89 * Black magic. A large debug stack is composed of 90 * multiple exception stack entries, which we 91 * iterate through now. Dont look: 92 */ 93 do { 94 ++j; 95 end -= EXCEPTION_STKSZ; 96 ids[j][4] = '1' + (j - N_EXCEPTION_STACKS); 97 } while (stack < end - EXCEPTION_STKSZ); 98 if (*usedp & (1U << j)) 99 break; 100 *usedp |= 1U << j; 101 *idp = ids[j]; 102 return (unsigned long *)end; 103 } 104 #endif 105 } 106 return NULL; 107 } 108 109 /* 110 * x86-64 can have up to three kernel stacks: 111 * process stack 112 * interrupt stack 113 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack 114 */ 115 116 static inline int valid_stack_ptr(struct thread_info *tinfo, 117 void *p, unsigned int size, void *end) 118 { 119 void *t = tinfo; 120 if (end) { 121 if (p < end && p >= (end-THREAD_SIZE)) 122 return 1; 123 else 124 return 0; 125 } 126 return p > t && p < t + THREAD_SIZE - size; 127 } 128 129 /* The form of the top of the frame on the stack */ 130 struct stack_frame { 131 struct stack_frame *next_frame; 132 unsigned long return_address; 133 }; 134 135 static inline unsigned long 136 print_context_stack(struct thread_info *tinfo, 137 unsigned long *stack, unsigned long bp, 138 const struct stacktrace_ops *ops, void *data, 139 unsigned long *end) 140 { 141 struct stack_frame *frame = (struct stack_frame *)bp; 142 143 while (valid_stack_ptr(tinfo, stack, sizeof(*stack), end)) { 144 unsigned long addr; 145 146 addr = *stack; 147 if (__kernel_text_address(addr)) { 148 if ((unsigned long) stack == bp + sizeof(long)) { 149 ops->address(data, addr, 1); 150 frame = frame->next_frame; 151 bp = (unsigned long) frame; 152 } else { 153 ops->address(data, addr, bp == 0); 154 } 155 } 156 stack++; 157 } 158 return bp; 159 } 160 161 void dump_trace(struct task_struct *task, struct pt_regs *regs, 162 unsigned long *stack, unsigned long bp, 163 const struct stacktrace_ops *ops, void *data) 164 { 165 const unsigned cpu = get_cpu(); 166 unsigned long *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr; 167 unsigned used = 0; 168 struct thread_info *tinfo; 169 170 if (!task) 171 task = current; 172 173 if (!stack) { 174 unsigned long dummy; 175 stack = &dummy; 176 if (task && task != current) 177 stack = (unsigned long *)task->thread.sp; 178 } 179 180 #ifdef CONFIG_FRAME_POINTER 181 if (!bp) { 182 if (task == current) { 183 /* Grab bp right from our regs */ 184 get_bp(bp); 185 } else { 186 /* bp is the last reg pushed by switch_to */ 187 bp = *(unsigned long *) task->thread.sp; 188 } 189 } 190 #endif 191 192 /* 193 * Print function call entries in all stacks, starting at the 194 * current stack address. If the stacks consist of nested 195 * exceptions 196 */ 197 tinfo = task_thread_info(task); 198 for (;;) { 199 char *id; 200 unsigned long *estack_end; 201 estack_end = in_exception_stack(cpu, (unsigned long)stack, 202 &used, &id); 203 204 if (estack_end) { 205 if (ops->stack(data, id) < 0) 206 break; 207 208 bp = print_context_stack(tinfo, stack, bp, ops, 209 data, estack_end); 210 ops->stack(data, "<EOE>"); 211 /* 212 * We link to the next stack via the 213 * second-to-last pointer (index -2 to end) in the 214 * exception stack: 215 */ 216 stack = (unsigned long *) estack_end[-2]; 217 continue; 218 } 219 if (irqstack_end) { 220 unsigned long *irqstack; 221 irqstack = irqstack_end - 222 (IRQSTACKSIZE - 64) / sizeof(*irqstack); 223 224 if (stack >= irqstack && stack < irqstack_end) { 225 if (ops->stack(data, "IRQ") < 0) 226 break; 227 bp = print_context_stack(tinfo, stack, bp, 228 ops, data, irqstack_end); 229 /* 230 * We link to the next stack (which would be 231 * the process stack normally) the last 232 * pointer (index -1 to end) in the IRQ stack: 233 */ 234 stack = (unsigned long *) (irqstack_end[-1]); 235 irqstack_end = NULL; 236 ops->stack(data, "EOI"); 237 continue; 238 } 239 } 240 break; 241 } 242 243 /* 244 * This handles the process stack: 245 */ 246 bp = print_context_stack(tinfo, stack, bp, ops, data, NULL); 247 put_cpu(); 248 } 249 EXPORT_SYMBOL(dump_trace); 250 251 static void 252 print_trace_warning_symbol(void *data, char *msg, unsigned long symbol) 253 { 254 printk(data); 255 print_symbol(msg, symbol); 256 printk("\n"); 257 } 258 259 static void print_trace_warning(void *data, char *msg) 260 { 261 printk("%s%s\n", (char *)data, msg); 262 } 263 264 static int print_trace_stack(void *data, char *name) 265 { 266 printk("%s <%s> ", (char *)data, name); 267 return 0; 268 } 269 270 /* 271 * Print one address/symbol entries per line. 272 */ 273 static void print_trace_address(void *data, unsigned long addr, int reliable) 274 { 275 touch_nmi_watchdog(); 276 printk(data); 277 printk_address(addr, reliable); 278 } 279 280 static const struct stacktrace_ops print_trace_ops = { 281 .warning = print_trace_warning, 282 .warning_symbol = print_trace_warning_symbol, 283 .stack = print_trace_stack, 284 .address = print_trace_address, 285 }; 286 287 static void 288 show_trace_log_lvl(struct task_struct *task, struct pt_regs *regs, 289 unsigned long *stack, unsigned long bp, char *log_lvl) 290 { 291 printk("%sCall Trace:\n", log_lvl); 292 dump_trace(task, regs, stack, bp, &print_trace_ops, log_lvl); 293 } 294 295 void show_trace(struct task_struct *task, struct pt_regs *regs, 296 unsigned long *stack, unsigned long bp) 297 { 298 show_trace_log_lvl(task, regs, stack, bp, ""); 299 } 300 301 static void 302 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, 303 unsigned long *sp, unsigned long bp, char *log_lvl) 304 { 305 unsigned long *stack; 306 int i; 307 const int cpu = smp_processor_id(); 308 unsigned long *irqstack_end = 309 (unsigned long *) (cpu_pda(cpu)->irqstackptr); 310 unsigned long *irqstack = 311 (unsigned long *) (cpu_pda(cpu)->irqstackptr - IRQSTACKSIZE); 312 313 /* 314 * debugging aid: "show_stack(NULL, NULL);" prints the 315 * back trace for this cpu. 316 */ 317 318 if (sp == NULL) { 319 if (task) 320 sp = (unsigned long *)task->thread.sp; 321 else 322 sp = (unsigned long *)&sp; 323 } 324 325 stack = sp; 326 for (i = 0; i < kstack_depth_to_print; i++) { 327 if (stack >= irqstack && stack <= irqstack_end) { 328 if (stack == irqstack_end) { 329 stack = (unsigned long *) (irqstack_end[-1]); 330 printk(" <EOI> "); 331 } 332 } else { 333 if (((long) stack & (THREAD_SIZE-1)) == 0) 334 break; 335 } 336 if (i && ((i % STACKSLOTS_PER_LINE) == 0)) 337 printk("\n%s", log_lvl); 338 printk(" %016lx", *stack++); 339 touch_nmi_watchdog(); 340 } 341 printk("\n"); 342 show_trace_log_lvl(task, regs, sp, bp, log_lvl); 343 } 344 345 void show_stack(struct task_struct *task, unsigned long *sp) 346 { 347 show_stack_log_lvl(task, NULL, sp, 0, ""); 348 } 349 350 /* 351 * The architecture-independent dump_stack generator 352 */ 353 void dump_stack(void) 354 { 355 unsigned long bp = 0; 356 unsigned long stack; 357 358 #ifdef CONFIG_FRAME_POINTER 359 if (!bp) 360 get_bp(bp); 361 #endif 362 363 printk("Pid: %d, comm: %.20s %s %s %.*s\n", 364 current->pid, current->comm, print_tainted(), 365 init_utsname()->release, 366 (int)strcspn(init_utsname()->version, " "), 367 init_utsname()->version); 368 show_trace(NULL, NULL, &stack, bp); 369 } 370 EXPORT_SYMBOL(dump_stack); 371 372 void show_registers(struct pt_regs *regs) 373 { 374 int i; 375 unsigned long sp; 376 const int cpu = smp_processor_id(); 377 struct task_struct *cur = cpu_pda(cpu)->pcurrent; 378 379 sp = regs->sp; 380 printk("CPU %d ", cpu); 381 __show_regs(regs, 1); 382 printk("Process %s (pid: %d, threadinfo %p, task %p)\n", 383 cur->comm, cur->pid, task_thread_info(cur), cur); 384 385 /* 386 * When in-kernel, we also print out the stack and code at the 387 * time of the fault.. 388 */ 389 if (!user_mode(regs)) { 390 unsigned int code_prologue = code_bytes * 43 / 64; 391 unsigned int code_len = code_bytes; 392 unsigned char c; 393 u8 *ip; 394 395 printk(KERN_EMERG "Stack:\n"); 396 show_stack_log_lvl(NULL, regs, (unsigned long *)sp, 397 regs->bp, KERN_EMERG); 398 399 printk(KERN_EMERG "Code: "); 400 401 ip = (u8 *)regs->ip - code_prologue; 402 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) { 403 /* try starting at IP */ 404 ip = (u8 *)regs->ip; 405 code_len = code_len - code_prologue + 1; 406 } 407 for (i = 0; i < code_len; i++, ip++) { 408 if (ip < (u8 *)PAGE_OFFSET || 409 probe_kernel_address(ip, c)) { 410 printk(" Bad RIP value."); 411 break; 412 } 413 if (ip == (u8 *)regs->ip) 414 printk("<%02x> ", c); 415 else 416 printk("%02x ", c); 417 } 418 } 419 printk("\n"); 420 } 421 422 int is_valid_bugaddr(unsigned long ip) 423 { 424 unsigned short ud2; 425 426 if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2))) 427 return 0; 428 429 return ud2 == 0x0b0f; 430 } 431 432 static raw_spinlock_t die_lock = __RAW_SPIN_LOCK_UNLOCKED; 433 static int die_owner = -1; 434 static unsigned int die_nest_count; 435 436 unsigned __kprobes long oops_begin(void) 437 { 438 int cpu; 439 unsigned long flags; 440 441 oops_enter(); 442 443 /* racy, but better than risking deadlock. */ 444 raw_local_irq_save(flags); 445 cpu = smp_processor_id(); 446 if (!__raw_spin_trylock(&die_lock)) { 447 if (cpu == die_owner) 448 /* nested oops. should stop eventually */; 449 else 450 __raw_spin_lock(&die_lock); 451 } 452 die_nest_count++; 453 die_owner = cpu; 454 console_verbose(); 455 bust_spinlocks(1); 456 return flags; 457 } 458 459 void __kprobes oops_end(unsigned long flags, struct pt_regs *regs, int signr) 460 { 461 die_owner = -1; 462 bust_spinlocks(0); 463 die_nest_count--; 464 if (!die_nest_count) 465 /* Nest count reaches zero, release the lock. */ 466 __raw_spin_unlock(&die_lock); 467 raw_local_irq_restore(flags); 468 if (!regs) { 469 oops_exit(); 470 return; 471 } 472 if (in_interrupt()) 473 panic("Fatal exception in interrupt"); 474 if (panic_on_oops) 475 panic("Fatal exception"); 476 oops_exit(); 477 do_exit(signr); 478 } 479 480 int __kprobes __die(const char *str, struct pt_regs *regs, long err) 481 { 482 printk(KERN_EMERG "%s: %04lx [#%d] ", str, err & 0xffff, ++die_counter); 483 #ifdef CONFIG_PREEMPT 484 printk("PREEMPT "); 485 #endif 486 #ifdef CONFIG_SMP 487 printk("SMP "); 488 #endif 489 #ifdef CONFIG_DEBUG_PAGEALLOC 490 printk("DEBUG_PAGEALLOC"); 491 #endif 492 printk("\n"); 493 sysfs_printk_last_file(); 494 if (notify_die(DIE_OOPS, str, regs, err, 495 current->thread.trap_no, SIGSEGV) == NOTIFY_STOP) 496 return 1; 497 498 show_registers(regs); 499 add_taint(TAINT_DIE); 500 /* Executive summary in case the oops scrolled away */ 501 printk(KERN_ALERT "RIP "); 502 printk_address(regs->ip, 1); 503 printk(" RSP <%016lx>\n", regs->sp); 504 if (kexec_should_crash(current)) 505 crash_kexec(regs); 506 return 0; 507 } 508 509 void die(const char *str, struct pt_regs *regs, long err) 510 { 511 unsigned long flags = oops_begin(); 512 513 if (!user_mode(regs)) 514 report_bug(regs->ip, regs); 515 516 if (__die(str, regs, err)) 517 regs = NULL; 518 oops_end(flags, regs, SIGSEGV); 519 } 520 521 notrace __kprobes void 522 die_nmi(char *str, struct pt_regs *regs, int do_panic) 523 { 524 unsigned long flags; 525 526 if (notify_die(DIE_NMIWATCHDOG, str, regs, 0, 2, SIGINT) == NOTIFY_STOP) 527 return; 528 529 flags = oops_begin(); 530 /* 531 * We are in trouble anyway, lets at least try 532 * to get a message out. 533 */ 534 printk(KERN_EMERG "%s", str); 535 printk(" on CPU%d, ip %08lx, registers:\n", 536 smp_processor_id(), regs->ip); 537 show_registers(regs); 538 if (kexec_should_crash(current)) 539 crash_kexec(regs); 540 if (do_panic || panic_on_oops) 541 panic("Non maskable interrupt"); 542 oops_end(flags, NULL, SIGBUS); 543 nmi_exit(); 544 local_irq_enable(); 545 do_exit(SIGBUS); 546 } 547 548 static int __init oops_setup(char *s) 549 { 550 if (!s) 551 return -EINVAL; 552 if (!strcmp(s, "panic")) 553 panic_on_oops = 1; 554 return 0; 555 } 556 early_param("oops", oops_setup); 557 558 static int __init kstack_setup(char *s) 559 { 560 if (!s) 561 return -EINVAL; 562 kstack_depth_to_print = simple_strtoul(s, NULL, 0); 563 return 0; 564 } 565 early_param("kstack", kstack_setup); 566 567 static int __init code_bytes_setup(char *s) 568 { 569 code_bytes = simple_strtoul(s, NULL, 0); 570 if (code_bytes > 8192) 571 code_bytes = 8192; 572 573 return 1; 574 } 575 __setup("code_bytes=", code_bytes_setup); 576