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 23 static char x86_stack_ids[][8] = { 24 [DEBUG_STACK - 1] = "#DB", 25 [NMI_STACK - 1] = "NMI", 26 [DOUBLEFAULT_STACK - 1] = "#DF", 27 [STACKFAULT_STACK - 1] = "#SS", 28 [MCE_STACK - 1] = "#MC", 29 #if DEBUG_STKSZ > EXCEPTION_STKSZ 30 [N_EXCEPTION_STACKS ... 31 N_EXCEPTION_STACKS + DEBUG_STKSZ / EXCEPTION_STKSZ - 2] = "#DB[?]" 32 #endif 33 }; 34 35 int x86_is_stack_id(int id, char *name) 36 { 37 return x86_stack_ids[id - 1] == name; 38 } 39 40 static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, 41 unsigned *usedp, char **idp) 42 { 43 unsigned k; 44 45 /* 46 * Iterate over all exception stacks, and figure out whether 47 * 'stack' is in one of them: 48 */ 49 for (k = 0; k < N_EXCEPTION_STACKS; k++) { 50 unsigned long end = per_cpu(orig_ist, cpu).ist[k]; 51 /* 52 * Is 'stack' above this exception frame's end? 53 * If yes then skip to the next frame. 54 */ 55 if (stack >= end) 56 continue; 57 /* 58 * Is 'stack' above this exception frame's start address? 59 * If yes then we found the right frame. 60 */ 61 if (stack >= end - EXCEPTION_STKSZ) { 62 /* 63 * Make sure we only iterate through an exception 64 * stack once. If it comes up for the second time 65 * then there's something wrong going on - just 66 * break out and return NULL: 67 */ 68 if (*usedp & (1U << k)) 69 break; 70 *usedp |= 1U << k; 71 *idp = x86_stack_ids[k]; 72 return (unsigned long *)end; 73 } 74 /* 75 * If this is a debug stack, and if it has a larger size than 76 * the usual exception stacks, then 'stack' might still 77 * be within the lower portion of the debug stack: 78 */ 79 #if DEBUG_STKSZ > EXCEPTION_STKSZ 80 if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) { 81 unsigned j = N_EXCEPTION_STACKS - 1; 82 83 /* 84 * Black magic. A large debug stack is composed of 85 * multiple exception stack entries, which we 86 * iterate through now. Dont look: 87 */ 88 do { 89 ++j; 90 end -= EXCEPTION_STKSZ; 91 x86_stack_ids[j][4] = '1' + 92 (j - N_EXCEPTION_STACKS); 93 } while (stack < end - EXCEPTION_STKSZ); 94 if (*usedp & (1U << j)) 95 break; 96 *usedp |= 1U << j; 97 *idp = x86_stack_ids[j]; 98 return (unsigned long *)end; 99 } 100 #endif 101 } 102 return NULL; 103 } 104 105 /* 106 * x86-64 can have up to three kernel stacks: 107 * process stack 108 * interrupt stack 109 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack 110 */ 111 112 void dump_trace(struct task_struct *task, struct pt_regs *regs, 113 unsigned long *stack, unsigned long bp, 114 const struct stacktrace_ops *ops, void *data) 115 { 116 const unsigned cpu = get_cpu(); 117 unsigned long *irq_stack_end = 118 (unsigned long *)per_cpu(irq_stack_ptr, cpu); 119 unsigned used = 0; 120 struct thread_info *tinfo; 121 int graph = 0; 122 123 if (!task) 124 task = current; 125 126 if (!stack) { 127 unsigned long dummy; 128 stack = &dummy; 129 if (task && task != current) 130 stack = (unsigned long *)task->thread.sp; 131 } 132 133 #ifdef CONFIG_FRAME_POINTER 134 if (!bp) { 135 if (task == current) { 136 /* Grab bp right from our regs */ 137 get_bp(bp); 138 } else { 139 /* bp is the last reg pushed by switch_to */ 140 bp = *(unsigned long *) task->thread.sp; 141 } 142 } 143 #endif 144 145 /* 146 * Print function call entries in all stacks, starting at the 147 * current stack address. If the stacks consist of nested 148 * exceptions 149 */ 150 tinfo = task_thread_info(task); 151 for (;;) { 152 char *id; 153 unsigned long *estack_end; 154 estack_end = in_exception_stack(cpu, (unsigned long)stack, 155 &used, &id); 156 157 if (estack_end) { 158 if (ops->stack(data, id) < 0) 159 break; 160 161 bp = print_context_stack(tinfo, stack, bp, ops, 162 data, estack_end, &graph); 163 ops->stack(data, "<EOE>"); 164 /* 165 * We link to the next stack via the 166 * second-to-last pointer (index -2 to end) in the 167 * exception stack: 168 */ 169 stack = (unsigned long *) estack_end[-2]; 170 continue; 171 } 172 if (irq_stack_end) { 173 unsigned long *irq_stack; 174 irq_stack = irq_stack_end - 175 (IRQ_STACK_SIZE - 64) / sizeof(*irq_stack); 176 177 if (stack >= irq_stack && stack < irq_stack_end) { 178 if (ops->stack(data, "IRQ") < 0) 179 break; 180 bp = print_context_stack(tinfo, stack, bp, 181 ops, data, irq_stack_end, &graph); 182 /* 183 * We link to the next stack (which would be 184 * the process stack normally) the last 185 * pointer (index -1 to end) in the IRQ stack: 186 */ 187 stack = (unsigned long *) (irq_stack_end[-1]); 188 irq_stack_end = NULL; 189 ops->stack(data, "EOI"); 190 continue; 191 } 192 } 193 break; 194 } 195 196 /* 197 * This handles the process stack: 198 */ 199 bp = print_context_stack(tinfo, stack, bp, ops, data, NULL, &graph); 200 put_cpu(); 201 } 202 EXPORT_SYMBOL(dump_trace); 203 204 void 205 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, 206 unsigned long *sp, unsigned long bp, char *log_lvl) 207 { 208 unsigned long *stack; 209 int i; 210 const int cpu = smp_processor_id(); 211 unsigned long *irq_stack_end = 212 (unsigned long *)(per_cpu(irq_stack_ptr, cpu)); 213 unsigned long *irq_stack = 214 (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE); 215 216 /* 217 * debugging aid: "show_stack(NULL, NULL);" prints the 218 * back trace for this cpu. 219 */ 220 221 if (sp == NULL) { 222 if (task) 223 sp = (unsigned long *)task->thread.sp; 224 else 225 sp = (unsigned long *)&sp; 226 } 227 228 stack = sp; 229 for (i = 0; i < kstack_depth_to_print; i++) { 230 if (stack >= irq_stack && stack <= irq_stack_end) { 231 if (stack == irq_stack_end) { 232 stack = (unsigned long *) (irq_stack_end[-1]); 233 printk(" <EOI> "); 234 } 235 } else { 236 if (((long) stack & (THREAD_SIZE-1)) == 0) 237 break; 238 } 239 if (i && ((i % STACKSLOTS_PER_LINE) == 0)) 240 printk("\n%s", log_lvl); 241 printk(" %016lx", *stack++); 242 touch_nmi_watchdog(); 243 } 244 printk("\n"); 245 show_trace_log_lvl(task, regs, sp, bp, log_lvl); 246 } 247 248 void show_registers(struct pt_regs *regs) 249 { 250 int i; 251 unsigned long sp; 252 const int cpu = smp_processor_id(); 253 struct task_struct *cur = current; 254 255 sp = regs->sp; 256 printk("CPU %d ", cpu); 257 __show_regs(regs, 1); 258 printk("Process %s (pid: %d, threadinfo %p, task %p)\n", 259 cur->comm, cur->pid, task_thread_info(cur), cur); 260 261 /* 262 * When in-kernel, we also print out the stack and code at the 263 * time of the fault.. 264 */ 265 if (!user_mode(regs)) { 266 unsigned int code_prologue = code_bytes * 43 / 64; 267 unsigned int code_len = code_bytes; 268 unsigned char c; 269 u8 *ip; 270 271 printk(KERN_EMERG "Stack:\n"); 272 show_stack_log_lvl(NULL, regs, (unsigned long *)sp, 273 regs->bp, KERN_EMERG); 274 275 printk(KERN_EMERG "Code: "); 276 277 ip = (u8 *)regs->ip - code_prologue; 278 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) { 279 /* try starting at IP */ 280 ip = (u8 *)regs->ip; 281 code_len = code_len - code_prologue + 1; 282 } 283 for (i = 0; i < code_len; i++, ip++) { 284 if (ip < (u8 *)PAGE_OFFSET || 285 probe_kernel_address(ip, c)) { 286 printk(" Bad RIP value."); 287 break; 288 } 289 if (ip == (u8 *)regs->ip) 290 printk("<%02x> ", c); 291 else 292 printk("%02x ", c); 293 } 294 } 295 printk("\n"); 296 } 297 298 int is_valid_bugaddr(unsigned long ip) 299 { 300 unsigned short ud2; 301 302 if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2))) 303 return 0; 304 305 return ud2 == 0x0b0f; 306 } 307 308