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/hardirq.h> 9 #include <linux/kdebug.h> 10 #include <linux/export.h> 11 #include <linux/ptrace.h> 12 #include <linux/kexec.h> 13 #include <linux/sysfs.h> 14 #include <linux/bug.h> 15 #include <linux/nmi.h> 16 17 #include <asm/stacktrace.h> 18 19 void stack_type_str(enum stack_type type, const char **begin, const char **end) 20 { 21 switch (type) { 22 case STACK_TYPE_IRQ: 23 case STACK_TYPE_SOFTIRQ: 24 *begin = "IRQ"; 25 *end = "EOI"; 26 break; 27 default: 28 *begin = NULL; 29 *end = NULL; 30 } 31 } 32 33 static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info) 34 { 35 unsigned long *begin = (unsigned long *)this_cpu_read(hardirq_stack); 36 unsigned long *end = begin + (THREAD_SIZE / sizeof(long)); 37 38 /* 39 * This is a software stack, so 'end' can be a valid stack pointer. 40 * It just means the stack is empty. 41 */ 42 if (stack < begin || stack > end) 43 return false; 44 45 info->type = STACK_TYPE_IRQ; 46 info->begin = begin; 47 info->end = end; 48 49 /* 50 * See irq_32.c -- the next stack pointer is stored at the beginning of 51 * the stack. 52 */ 53 info->next_sp = (unsigned long *)*begin; 54 55 return true; 56 } 57 58 static bool in_softirq_stack(unsigned long *stack, struct stack_info *info) 59 { 60 unsigned long *begin = (unsigned long *)this_cpu_read(softirq_stack); 61 unsigned long *end = begin + (THREAD_SIZE / sizeof(long)); 62 63 /* 64 * This is a software stack, so 'end' can be a valid stack pointer. 65 * It just means the stack is empty. 66 */ 67 if (stack < begin || stack > end) 68 return false; 69 70 info->type = STACK_TYPE_SOFTIRQ; 71 info->begin = begin; 72 info->end = end; 73 74 /* 75 * The next stack pointer is stored at the beginning of the stack. 76 * See irq_32.c. 77 */ 78 info->next_sp = (unsigned long *)*begin; 79 80 return true; 81 } 82 83 int get_stack_info(unsigned long *stack, struct task_struct *task, 84 struct stack_info *info, unsigned long *visit_mask) 85 { 86 if (!stack) 87 goto unknown; 88 89 task = task ? : current; 90 91 if (in_task_stack(stack, task, info)) 92 return 0; 93 94 if (task != current) 95 goto unknown; 96 97 if (in_hardirq_stack(stack, info)) 98 return 0; 99 100 if (in_softirq_stack(stack, info)) 101 return 0; 102 103 unknown: 104 info->type = STACK_TYPE_UNKNOWN; 105 return -EINVAL; 106 } 107 108 void dump_trace(struct task_struct *task, struct pt_regs *regs, 109 unsigned long *stack, unsigned long bp, 110 const struct stacktrace_ops *ops, void *data) 111 { 112 unsigned long visit_mask = 0; 113 int graph = 0; 114 115 task = task ? : current; 116 stack = stack ? : get_stack_pointer(task, regs); 117 bp = bp ? : (unsigned long)get_frame_pointer(task, regs); 118 119 for (;;) { 120 const char *begin_str, *end_str; 121 struct stack_info info; 122 123 if (get_stack_info(stack, task, &info, &visit_mask)) 124 break; 125 126 stack_type_str(info.type, &begin_str, &end_str); 127 128 if (begin_str && ops->stack(data, begin_str) < 0) 129 break; 130 131 bp = ops->walk_stack(task, stack, bp, ops, data, &info, &graph); 132 133 if (end_str && ops->stack(data, end_str) < 0) 134 break; 135 136 stack = info.next_sp; 137 138 touch_nmi_watchdog(); 139 } 140 } 141 EXPORT_SYMBOL(dump_trace); 142 143 void 144 show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, 145 unsigned long *sp, unsigned long bp, char *log_lvl) 146 { 147 unsigned long *stack; 148 int i; 149 150 sp = sp ? : get_stack_pointer(task, regs); 151 152 stack = sp; 153 for (i = 0; i < kstack_depth_to_print; i++) { 154 if (kstack_end(stack)) 155 break; 156 if ((i % STACKSLOTS_PER_LINE) == 0) { 157 if (i != 0) 158 pr_cont("\n"); 159 printk("%s %08lx", log_lvl, *stack++); 160 } else 161 pr_cont(" %08lx", *stack++); 162 touch_nmi_watchdog(); 163 } 164 pr_cont("\n"); 165 show_trace_log_lvl(task, regs, sp, bp, log_lvl); 166 } 167 168 169 void show_regs(struct pt_regs *regs) 170 { 171 int i; 172 173 show_regs_print_info(KERN_EMERG); 174 __show_regs(regs, !user_mode(regs)); 175 176 /* 177 * When in-kernel, we also print out the stack and code at the 178 * time of the fault.. 179 */ 180 if (!user_mode(regs)) { 181 unsigned int code_prologue = code_bytes * 43 / 64; 182 unsigned int code_len = code_bytes; 183 unsigned char c; 184 u8 *ip; 185 186 pr_emerg("Stack:\n"); 187 show_stack_log_lvl(NULL, regs, NULL, 0, KERN_EMERG); 188 189 pr_emerg("Code:"); 190 191 ip = (u8 *)regs->ip - code_prologue; 192 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) { 193 /* try starting at IP */ 194 ip = (u8 *)regs->ip; 195 code_len = code_len - code_prologue + 1; 196 } 197 for (i = 0; i < code_len; i++, ip++) { 198 if (ip < (u8 *)PAGE_OFFSET || 199 probe_kernel_address(ip, c)) { 200 pr_cont(" Bad EIP value."); 201 break; 202 } 203 if (ip == (u8 *)regs->ip) 204 pr_cont(" <%02x>", c); 205 else 206 pr_cont(" %02x", c); 207 } 208 } 209 pr_cont("\n"); 210 } 211 212 int is_valid_bugaddr(unsigned long ip) 213 { 214 unsigned short ud2; 215 216 if (ip < PAGE_OFFSET) 217 return 0; 218 if (probe_kernel_address((unsigned short *)ip, ud2)) 219 return 0; 220 221 return ud2 == 0x0b0f; 222 } 223