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 goto recursion_check; 93 94 if (task != current) 95 goto unknown; 96 97 if (in_hardirq_stack(stack, info)) 98 goto recursion_check; 99 100 if (in_softirq_stack(stack, info)) 101 goto recursion_check; 102 103 goto unknown; 104 105 recursion_check: 106 /* 107 * Make sure we don't iterate through any given stack more than once. 108 * If it comes up a second time then there's something wrong going on: 109 * just break out and report an unknown stack type. 110 */ 111 if (visit_mask) { 112 if (*visit_mask & (1UL << info->type)) 113 goto unknown; 114 *visit_mask |= 1UL << info->type; 115 } 116 117 return 0; 118 119 unknown: 120 info->type = STACK_TYPE_UNKNOWN; 121 return -EINVAL; 122 } 123 124 void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs, 125 unsigned long *sp, char *log_lvl) 126 { 127 unsigned long *stack; 128 int i; 129 130 if (!try_get_task_stack(task)) 131 return; 132 133 sp = sp ? : get_stack_pointer(task, regs); 134 135 stack = sp; 136 for (i = 0; i < kstack_depth_to_print; i++) { 137 if (kstack_end(stack)) 138 break; 139 if ((i % STACKSLOTS_PER_LINE) == 0) { 140 if (i != 0) 141 pr_cont("\n"); 142 printk("%s %08lx", log_lvl, *stack++); 143 } else 144 pr_cont(" %08lx", *stack++); 145 touch_nmi_watchdog(); 146 } 147 pr_cont("\n"); 148 show_trace_log_lvl(task, regs, sp, log_lvl); 149 150 put_task_stack(task); 151 } 152 153 154 void show_regs(struct pt_regs *regs) 155 { 156 int i; 157 158 show_regs_print_info(KERN_EMERG); 159 __show_regs(regs, !user_mode(regs)); 160 161 /* 162 * When in-kernel, we also print out the stack and code at the 163 * time of the fault.. 164 */ 165 if (!user_mode(regs)) { 166 unsigned int code_prologue = code_bytes * 43 / 64; 167 unsigned int code_len = code_bytes; 168 unsigned char c; 169 u8 *ip; 170 171 pr_emerg("Stack:\n"); 172 show_stack_log_lvl(current, regs, NULL, KERN_EMERG); 173 174 pr_emerg("Code:"); 175 176 ip = (u8 *)regs->ip - code_prologue; 177 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) { 178 /* try starting at IP */ 179 ip = (u8 *)regs->ip; 180 code_len = code_len - code_prologue + 1; 181 } 182 for (i = 0; i < code_len; i++, ip++) { 183 if (ip < (u8 *)PAGE_OFFSET || 184 probe_kernel_address(ip, c)) { 185 pr_cont(" Bad EIP value."); 186 break; 187 } 188 if (ip == (u8 *)regs->ip) 189 pr_cont(" <%02x>", c); 190 else 191 pr_cont(" %02x", c); 192 } 193 } 194 pr_cont("\n"); 195 } 196 197 int is_valid_bugaddr(unsigned long ip) 198 { 199 unsigned short ud2; 200 201 if (ip < PAGE_OFFSET) 202 return 0; 203 if (probe_kernel_address((unsigned short *)ip, ud2)) 204 return 0; 205 206 return ud2 == 0x0b0f; 207 } 208