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
stack_type_str(enum stack_type type,const char ** begin,const char ** end)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
in_hardirq_stack(unsigned long * stack,struct stack_info * info)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
in_softirq_stack(unsigned long * stack,struct stack_info * info)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
get_stack_info(unsigned long * stack,struct task_struct * task,struct stack_info * info,unsigned long * visit_mask)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
show_stack_log_lvl(struct task_struct * task,struct pt_regs * regs,unsigned long * sp,char * log_lvl)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
show_regs(struct pt_regs * regs)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
is_valid_bugaddr(unsigned long ip)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