1 // SPDX-License-Identifier: GPL-2.0
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
6 #include <linux/sched/debug.h>
7 #include <linux/kallsyms.h>
8 #include <linux/kprobes.h>
9 #include <linux/uaccess.h>
10 #include <linux/hardirq.h>
11 #include <linux/kdebug.h>
12 #include <linux/export.h>
13 #include <linux/ptrace.h>
14 #include <linux/kexec.h>
15 #include <linux/sysfs.h>
16 #include <linux/bug.h>
17 #include <linux/nmi.h>
19 #include <asm/stacktrace.h>
21 static char *exception_stack_names[N_EXCEPTION_STACKS] = {
22 [ DOUBLEFAULT_STACK-1 ] = "#DF",
23 [ NMI_STACK-1 ] = "NMI",
24 [ DEBUG_STACK-1 ] = "#DB",
25 [ MCE_STACK-1 ] = "#MC",
28 static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
29 [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ,
30 [DEBUG_STACK - 1] = DEBUG_STKSZ
33 const char *stack_type_name(enum stack_type type)
35 BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
37 if (type == STACK_TYPE_IRQ)
40 if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)
41 return exception_stack_names[type - STACK_TYPE_EXCEPTION];
46 static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
48 unsigned long *begin, *end;
52 BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
54 for (k = 0; k < N_EXCEPTION_STACKS; k++) {
55 end = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k];
56 begin = end - (exception_stack_sizes[k] / sizeof(long));
57 regs = (struct pt_regs *)end - 1;
59 if (stack <= begin || stack >= end)
62 info->type = STACK_TYPE_EXCEPTION + k;
65 info->next_sp = (unsigned long *)regs->sp;
73 static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
75 unsigned long *end = (unsigned long *)this_cpu_read(irq_stack_ptr);
76 unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
79 * This is a software stack, so 'end' can be a valid stack pointer.
80 * It just means the stack is empty.
82 if (stack <= begin || stack > end)
85 info->type = STACK_TYPE_IRQ;
90 * The next stack pointer is the first thing pushed by the entry code
91 * after switching to the irq stack.
93 info->next_sp = (unsigned long *)*(end - 1);
98 int get_stack_info(unsigned long *stack, struct task_struct *task,
99 struct stack_info *info, unsigned long *visit_mask)
104 task = task ? : current;
106 if (in_task_stack(stack, task, info))
107 goto recursion_check;
112 if (in_exception_stack(stack, info))
113 goto recursion_check;
115 if (in_irq_stack(stack, info))
116 goto recursion_check;
122 * Make sure we don't iterate through any given stack more than once.
123 * If it comes up a second time then there's something wrong going on:
124 * just break out and report an unknown stack type.
127 if (*visit_mask & (1UL << info->type)) {
128 printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
131 *visit_mask |= 1UL << info->type;
137 info->type = STACK_TYPE_UNKNOWN;
141 void show_regs(struct pt_regs *regs)
145 show_regs_print_info(KERN_DEFAULT);
146 __show_regs(regs, 1);
149 * When in-kernel, we also print out the stack and code at the
150 * time of the fault..
152 if (!user_mode(regs)) {
153 unsigned int code_prologue = code_bytes * 43 / 64;
154 unsigned int code_len = code_bytes;
158 show_trace_log_lvl(current, regs, NULL, KERN_DEFAULT);
160 printk(KERN_DEFAULT "Code: ");
162 ip = (u8 *)regs->ip - code_prologue;
163 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
164 /* try starting at IP */
166 code_len = code_len - code_prologue + 1;
168 for (i = 0; i < code_len; i++, ip++) {
169 if (ip < (u8 *)PAGE_OFFSET ||
170 probe_kernel_address(ip, c)) {
171 pr_cont(" Bad RIP value.");
174 if (ip == (u8 *)regs->ip)
175 pr_cont("<%02x> ", c);