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 *irqstack_end = (unsigned long *)cpu_pda(cpu)->irqstackptr; 110 unsigned used = 0; 111 struct thread_info *tinfo; 112 113 if (!task) 114 task = current; 115 116 if (!stack) { 117 unsigned long dummy; 118 stack = &dummy; 119 if (task && task != current) 120 stack = (unsigned long *)task->thread.sp; 121 } 122 123 #ifdef CONFIG_FRAME_POINTER 124 if (!bp) { 125 if (task == current) { 126 /* Grab bp right from our regs */ 127 get_bp(bp); 128 } else { 129 /* bp is the last reg pushed by switch_to */ 130 bp = *(unsigned long *) task->thread.sp; 131 } 132 } 133 #endif 134 135 /* 136 * Print function call entries in all stacks, starting at the 137 * current stack address. If the stacks consist of nested 138 * exceptions 139 */ 140 tinfo = task_thread_info(task); 141 for (;;) { 142 char *id; 143 unsigned long *estack_end; 144 estack_end = in_exception_stack(cpu, (unsigned long)stack, 145 &used, &id); 146 147 if (estack_end) { 148 if (ops->stack(data, id) < 0) 149 break; 150 151 bp = print_context_stack(tinfo, stack, bp, ops, 152 data, estack_end); 153 ops->stack(data, "<EOE>"); 154 /* 155 * We link to the next stack via the 156 * second-to-last pointer (index -2 to end) in the 157 * exception stack: 158 */ 159 stack = (unsigned long *) estack_end[-2]; 160 continue; 161 } 162 if (irqstack_end) { 163 unsigned long *irqstack; 164 irqstack = irqstack_end - 165 (IRQSTACKSIZE - 64) / sizeof(*irqstack); 166 167 if (stack >= irqstack && stack < irqstack_end) { 168 if (ops->stack(data, "IRQ") < 0) 169 break; 170 bp = print_context_stack(tinfo, stack, bp, 171 ops, data, irqstack_end); 172 /* 173 * We link to the next stack (which would be 174 * the process stack normally) the last 175 * pointer (index -1 to end) in the IRQ stack: 176 */ 177 stack = (unsigned long *) (irqstack_end[-1]); 178 irqstack_end = NULL; 179 ops->stack(data, "EOI"); 180 continue; 181 } 182 } 183 break; 184 } 185 186 /* 187 * This handles the process stack: 188 */ 189 bp = print_context_stack(tinfo, stack, bp, ops, data, NULL); 190 put_cpu(); 191 } 192 EXPORT_SYMBOL(dump_trace); 193 194 void 195 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, 196 unsigned long *sp, unsigned long bp, char *log_lvl) 197 { 198 unsigned long *stack; 199 int i; 200 const int cpu = smp_processor_id(); 201 unsigned long *irqstack_end = 202 (unsigned long *) (cpu_pda(cpu)->irqstackptr); 203 unsigned long *irqstack = 204 (unsigned long *) (cpu_pda(cpu)->irqstackptr - IRQSTACKSIZE); 205 206 /* 207 * debugging aid: "show_stack(NULL, NULL);" prints the 208 * back trace for this cpu. 209 */ 210 211 if (sp == NULL) { 212 if (task) 213 sp = (unsigned long *)task->thread.sp; 214 else 215 sp = (unsigned long *)&sp; 216 } 217 218 stack = sp; 219 for (i = 0; i < kstack_depth_to_print; i++) { 220 if (stack >= irqstack && stack <= irqstack_end) { 221 if (stack == irqstack_end) { 222 stack = (unsigned long *) (irqstack_end[-1]); 223 printk(" <EOI> "); 224 } 225 } else { 226 if (((long) stack & (THREAD_SIZE-1)) == 0) 227 break; 228 } 229 if (i && ((i % STACKSLOTS_PER_LINE) == 0)) 230 printk("\n%s", log_lvl); 231 printk(" %016lx", *stack++); 232 touch_nmi_watchdog(); 233 } 234 printk("\n"); 235 show_trace_log_lvl(task, regs, sp, bp, log_lvl); 236 } 237 238 void show_registers(struct pt_regs *regs) 239 { 240 int i; 241 unsigned long sp; 242 const int cpu = smp_processor_id(); 243 struct task_struct *cur = cpu_pda(cpu)->pcurrent; 244 245 sp = regs->sp; 246 printk("CPU %d ", cpu); 247 __show_regs(regs, 1); 248 printk("Process %s (pid: %d, threadinfo %p, task %p)\n", 249 cur->comm, cur->pid, task_thread_info(cur), cur); 250 251 /* 252 * When in-kernel, we also print out the stack and code at the 253 * time of the fault.. 254 */ 255 if (!user_mode(regs)) { 256 unsigned int code_prologue = code_bytes * 43 / 64; 257 unsigned int code_len = code_bytes; 258 unsigned char c; 259 u8 *ip; 260 261 printk(KERN_EMERG "Stack:\n"); 262 show_stack_log_lvl(NULL, regs, (unsigned long *)sp, 263 regs->bp, KERN_EMERG); 264 265 printk(KERN_EMERG "Code: "); 266 267 ip = (u8 *)regs->ip - code_prologue; 268 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) { 269 /* try starting at IP */ 270 ip = (u8 *)regs->ip; 271 code_len = code_len - code_prologue + 1; 272 } 273 for (i = 0; i < code_len; i++, ip++) { 274 if (ip < (u8 *)PAGE_OFFSET || 275 probe_kernel_address(ip, c)) { 276 printk(" Bad RIP value."); 277 break; 278 } 279 if (ip == (u8 *)regs->ip) 280 printk("<%02x> ", c); 281 else 282 printk("%02x ", c); 283 } 284 } 285 printk("\n"); 286 } 287 288 int is_valid_bugaddr(unsigned long ip) 289 { 290 unsigned short ud2; 291 292 if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2))) 293 return 0; 294 295 return ud2 == 0x0b0f; 296 } 297 298