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 #include "dumpstack.h" 21 22 static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, 23 unsigned *usedp, char **idp) 24 { 25 static char ids[][8] = { 26 [DEBUG_STACK - 1] = "#DB", 27 [NMI_STACK - 1] = "NMI", 28 [DOUBLEFAULT_STACK - 1] = "#DF", 29 [STACKFAULT_STACK - 1] = "#SS", 30 [MCE_STACK - 1] = "#MC", 31 #if DEBUG_STKSZ > EXCEPTION_STKSZ 32 [N_EXCEPTION_STACKS ... 33 N_EXCEPTION_STACKS + DEBUG_STKSZ / EXCEPTION_STKSZ - 2] = "#DB[?]" 34 #endif 35 }; 36 unsigned k; 37 38 /* 39 * Iterate over all exception stacks, and figure out whether 40 * 'stack' is in one of them: 41 */ 42 for (k = 0; k < N_EXCEPTION_STACKS; k++) { 43 unsigned long end = per_cpu(orig_ist, cpu).ist[k]; 44 /* 45 * Is 'stack' above this exception frame's end? 46 * If yes then skip to the next frame. 47 */ 48 if (stack >= end) 49 continue; 50 /* 51 * Is 'stack' above this exception frame's start address? 52 * If yes then we found the right frame. 53 */ 54 if (stack >= end - EXCEPTION_STKSZ) { 55 /* 56 * Make sure we only iterate through an exception 57 * stack once. If it comes up for the second time 58 * then there's something wrong going on - just 59 * break out and return NULL: 60 */ 61 if (*usedp & (1U << k)) 62 break; 63 *usedp |= 1U << k; 64 *idp = ids[k]; 65 return (unsigned long *)end; 66 } 67 /* 68 * If this is a debug stack, and if it has a larger size than 69 * the usual exception stacks, then 'stack' might still 70 * be within the lower portion of the debug stack: 71 */ 72 #if DEBUG_STKSZ > EXCEPTION_STKSZ 73 if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) { 74 unsigned j = N_EXCEPTION_STACKS - 1; 75 76 /* 77 * Black magic. A large debug stack is composed of 78 * multiple exception stack entries, which we 79 * iterate through now. Dont look: 80 */ 81 do { 82 ++j; 83 end -= EXCEPTION_STKSZ; 84 ids[j][4] = '1' + (j - N_EXCEPTION_STACKS); 85 } while (stack < end - EXCEPTION_STKSZ); 86 if (*usedp & (1U << j)) 87 break; 88 *usedp |= 1U << j; 89 *idp = ids[j]; 90 return (unsigned long *)end; 91 } 92 #endif 93 } 94 return NULL; 95 } 96 97 /* 98 * x86-64 can have up to three kernel stacks: 99 * process stack 100 * interrupt stack 101 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack 102 */ 103 104 void dump_trace(struct task_struct *task, struct pt_regs *regs, 105 unsigned long *stack, unsigned long bp, 106 const struct stacktrace_ops *ops, void *data) 107 { 108 const unsigned cpu = get_cpu(); 109 unsigned long *irq_stack_end = 110 (unsigned long *)per_cpu(irq_stack_ptr, cpu); 111 unsigned used = 0; 112 struct thread_info *tinfo; 113 int graph = 0; 114 115 if (!task) 116 task = current; 117 118 if (!stack) { 119 unsigned long dummy; 120 stack = &dummy; 121 if (task && task != current) 122 stack = (unsigned long *)task->thread.sp; 123 } 124 125 #ifdef CONFIG_FRAME_POINTER 126 if (!bp) { 127 if (task == current) { 128 /* Grab bp right from our regs */ 129 get_bp(bp); 130 } else { 131 /* bp is the last reg pushed by switch_to */ 132 bp = *(unsigned long *) task->thread.sp; 133 } 134 } 135 #endif 136 137 /* 138 * Print function call entries in all stacks, starting at the 139 * current stack address. If the stacks consist of nested 140 * exceptions 141 */ 142 tinfo = task_thread_info(task); 143 for (;;) { 144 char *id; 145 unsigned long *estack_end; 146 estack_end = in_exception_stack(cpu, (unsigned long)stack, 147 &used, &id); 148 149 if (estack_end) { 150 if (ops->stack(data, id) < 0) 151 break; 152 153 bp = print_context_stack(tinfo, stack, bp, ops, 154 data, estack_end, &graph); 155 ops->stack(data, "<EOE>"); 156 /* 157 * We link to the next stack via the 158 * second-to-last pointer (index -2 to end) in the 159 * exception stack: 160 */ 161 stack = (unsigned long *) estack_end[-2]; 162 continue; 163 } 164 if (irq_stack_end) { 165 unsigned long *irq_stack; 166 irq_stack = irq_stack_end - 167 (IRQ_STACK_SIZE - 64) / sizeof(*irq_stack); 168 169 if (stack >= irq_stack && stack < irq_stack_end) { 170 if (ops->stack(data, "IRQ") < 0) 171 break; 172 bp = print_context_stack(tinfo, stack, bp, 173 ops, data, irq_stack_end, &graph); 174 /* 175 * We link to the next stack (which would be 176 * the process stack normally) the last 177 * pointer (index -1 to end) in the IRQ stack: 178 */ 179 stack = (unsigned long *) (irq_stack_end[-1]); 180 irq_stack_end = NULL; 181 ops->stack(data, "EOI"); 182 continue; 183 } 184 } 185 break; 186 } 187 188 /* 189 * This handles the process stack: 190 */ 191 bp = print_context_stack(tinfo, stack, bp, ops, data, NULL, &graph); 192 put_cpu(); 193 } 194 EXPORT_SYMBOL(dump_trace); 195 196 void 197 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, 198 unsigned long *sp, unsigned long bp, char *log_lvl) 199 { 200 unsigned long *stack; 201 int i; 202 const int cpu = smp_processor_id(); 203 unsigned long *irq_stack_end = 204 (unsigned long *)(per_cpu(irq_stack_ptr, cpu)); 205 unsigned long *irq_stack = 206 (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE); 207 208 /* 209 * debugging aid: "show_stack(NULL, NULL);" prints the 210 * back trace for this cpu. 211 */ 212 213 if (sp == NULL) { 214 if (task) 215 sp = (unsigned long *)task->thread.sp; 216 else 217 sp = (unsigned long *)&sp; 218 } 219 220 stack = sp; 221 for (i = 0; i < kstack_depth_to_print; i++) { 222 if (stack >= irq_stack && stack <= irq_stack_end) { 223 if (stack == irq_stack_end) { 224 stack = (unsigned long *) (irq_stack_end[-1]); 225 printk(" <EOI> "); 226 } 227 } else { 228 if (((long) stack & (THREAD_SIZE-1)) == 0) 229 break; 230 } 231 if (i && ((i % STACKSLOTS_PER_LINE) == 0)) 232 printk("\n%s", log_lvl); 233 printk(" %016lx", *stack++); 234 touch_nmi_watchdog(); 235 } 236 printk("\n"); 237 show_trace_log_lvl(task, regs, sp, bp, log_lvl); 238 } 239 240 void show_registers(struct pt_regs *regs) 241 { 242 int i; 243 unsigned long sp; 244 const int cpu = smp_processor_id(); 245 struct task_struct *cur = current; 246 247 sp = regs->sp; 248 printk("CPU %d ", cpu); 249 __show_regs(regs, 1); 250 printk("Process %s (pid: %d, threadinfo %p, task %p)\n", 251 cur->comm, cur->pid, task_thread_info(cur), cur); 252 253 /* 254 * When in-kernel, we also print out the stack and code at the 255 * time of the fault.. 256 */ 257 if (!user_mode(regs)) { 258 unsigned int code_prologue = code_bytes * 43 / 64; 259 unsigned int code_len = code_bytes; 260 unsigned char c; 261 u8 *ip; 262 263 printk(KERN_EMERG "Stack:\n"); 264 show_stack_log_lvl(NULL, regs, (unsigned long *)sp, 265 regs->bp, KERN_EMERG); 266 267 printk(KERN_EMERG "Code: "); 268 269 ip = (u8 *)regs->ip - code_prologue; 270 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) { 271 /* try starting at IP */ 272 ip = (u8 *)regs->ip; 273 code_len = code_len - code_prologue + 1; 274 } 275 for (i = 0; i < code_len; i++, ip++) { 276 if (ip < (u8 *)PAGE_OFFSET || 277 probe_kernel_address(ip, c)) { 278 printk(" Bad RIP value."); 279 break; 280 } 281 if (ip == (u8 *)regs->ip) 282 printk("<%02x> ", c); 283 else 284 printk("%02x ", c); 285 } 286 } 287 printk("\n"); 288 } 289 290 int is_valid_bugaddr(unsigned long ip) 291 { 292 unsigned short ud2; 293 294 if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2))) 295 return 0; 296 297 return ud2 == 0x0b0f; 298 } 299 300