arch/x86/kernel/dumpstack_32.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  Copyright (C) 1991, 1992  Linus Torvalds
   4  *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
   5  */
   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>
  18
  19 #include <asm/stacktrace.h>
  20
  21 const char *stack_type_name(enum stack_type type)
  22 {
  23         if (type == STACK_TYPE_IRQ)
  24                 return "IRQ";
  25
  26         if (type == STACK_TYPE_SOFTIRQ)
  27                 return "SOFTIRQ";
  28
  29         if (type == STACK_TYPE_ENTRY)
  30                 return "ENTRY_TRAMPOLINE";
  31
  32         return NULL;
  33 }
  34
  35 static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info)
  36 {
  37         unsigned long *begin = (unsigned long *)this_cpu_read(hardirq_stack);
  38         unsigned long *end   = begin + (THREAD_SIZE / sizeof(long));
  39
  40         /*
  41          * This is a software stack, so 'end' can be a valid stack pointer.
  42          * It just means the stack is empty.
  43          */
  44         if (stack <= begin || stack > end)
  45                 return false;
  46
  47         info->type      = STACK_TYPE_IRQ;
  48         info->begin     = begin;
  49         info->end       = end;
  50
  51         /*
  52          * See irq_32.c -- the next stack pointer is stored at the beginning of
  53          * the stack.
  54          */
  55         info->next_sp   = (unsigned long *)*begin;
  56
  57         return true;
  58 }
  59
  60 static bool in_softirq_stack(unsigned long *stack, struct stack_info *info)
  61 {
  62         unsigned long *begin = (unsigned long *)this_cpu_read(softirq_stack);
  63         unsigned long *end   = begin + (THREAD_SIZE / sizeof(long));
  64
  65         /*
  66          * This is a software stack, so 'end' can be a valid stack pointer.
  67          * It just means the stack is empty.
  68          */
  69         if (stack <= begin || stack > end)
  70                 return false;
  71
  72         info->type      = STACK_TYPE_SOFTIRQ;
  73         info->begin     = begin;
  74         info->end       = end;
  75
  76         /*
  77          * The next stack pointer is stored at the beginning of the stack.
  78          * See irq_32.c.
  79          */
  80         info->next_sp   = (unsigned long *)*begin;
  81
  82         return true;
  83 }
  84
  85 int get_stack_info(unsigned long *stack, struct task_struct *task,
  86                    struct stack_info *info, unsigned long *visit_mask)
  87 {
  88         if (!stack)
  89                 goto unknown;
  90
  91         task = task ? : current;
  92
  93         if (in_task_stack(stack, task, info))
  94                 goto recursion_check;
  95
  96         if (task != current)
  97                 goto unknown;
  98
  99         if (in_entry_stack(stack, info))
 100                 goto recursion_check;
 101
 102         if (in_hardirq_stack(stack, info))
 103                 goto recursion_check;
 104
 105         if (in_softirq_stack(stack, info))
 106                 goto recursion_check;
 107
 108         goto unknown;
 109
 110 recursion_check:
 111         /*
 112          * Make sure we don't iterate through any given stack more than once.
 113          * If it comes up a second time then there's something wrong going on:
 114          * just break out and report an unknown stack type.
 115          */
 116         if (visit_mask) {
 117                 if (*visit_mask & (1UL << info->type)) {
 118                         printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
 119                         goto unknown;
 120                 }
 121                 *visit_mask |= 1UL << info->type;
 122         }
 123
 124         return 0;
 125
 126 unknown:
 127         info->type = STACK_TYPE_UNKNOWN;
 128         return -EINVAL;
 129 }
 130
 131 void show_regs(struct pt_regs *regs)
 132 {
 133         int i;
 134
 135         show_regs_print_info(KERN_EMERG);
 136         __show_regs(regs, !user_mode(regs));
 137
 138         /*
 139          * When in-kernel, we also print out the stack and code at the
 140          * time of the fault..
 141          */
 142         if (!user_mode(regs)) {
 143                 unsigned int code_prologue = code_bytes * 43 / 64;
 144                 unsigned int code_len = code_bytes;
 145                 unsigned char c;
 146                 u8 *ip;
 147
 148                 show_trace_log_lvl(current, regs, NULL, KERN_EMERG);
 149
 150                 pr_emerg("Code:");
 151
 152                 ip = (u8 *)regs->ip - code_prologue;
 153                 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
 154                         /* try starting at IP */
 155                         ip = (u8 *)regs->ip;
 156                         code_len = code_len - code_prologue + 1;
 157                 }
 158                 for (i = 0; i < code_len; i++, ip++) {
 159                         if (ip < (u8 *)PAGE_OFFSET ||
 160                                         probe_kernel_address(ip, c)) {
 161                                 pr_cont("  Bad EIP value.");
 162                                 break;
 163                         }
 164                         if (ip == (u8 *)regs->ip)
 165                                 pr_cont(" <%02x>", c);
 166                         else
 167                                 pr_cont(" %02x", c);
 168                 }
 169         }
 170         pr_cont("\n");
 171 }