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 stack_type_name(enum stack_type type)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 if (type == STACK_TYPE_EXCEPTION) 33 return "#DF"; 34 35 return NULL; 36 } 37 in_hardirq_stack(unsigned long * stack,struct stack_info * info)38 static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info) 39 { 40 unsigned long *begin = (unsigned long *)this_cpu_read(pcpu_hot.hardirq_stack_ptr); 41 unsigned long *end = begin + (THREAD_SIZE / sizeof(long)); 42 43 /* 44 * This is a software stack, so 'end' can be a valid stack pointer. 45 * It just means the stack is empty. 46 */ 47 if (stack < begin || stack > end) 48 return false; 49 50 info->type = STACK_TYPE_IRQ; 51 info->begin = begin; 52 info->end = end; 53 54 /* 55 * See irq_32.c -- the next stack pointer is stored at the beginning of 56 * the stack. 57 */ 58 info->next_sp = (unsigned long *)*begin; 59 60 return true; 61 } 62 in_softirq_stack(unsigned long * stack,struct stack_info * info)63 static bool in_softirq_stack(unsigned long *stack, struct stack_info *info) 64 { 65 unsigned long *begin = (unsigned long *)this_cpu_read(pcpu_hot.softirq_stack_ptr); 66 unsigned long *end = begin + (THREAD_SIZE / sizeof(long)); 67 68 /* 69 * This is a software stack, so 'end' can be a valid stack pointer. 70 * It just means the stack is empty. 71 */ 72 if (stack < begin || stack > end) 73 return false; 74 75 info->type = STACK_TYPE_SOFTIRQ; 76 info->begin = begin; 77 info->end = end; 78 79 /* 80 * The next stack pointer is stored at the beginning of the stack. 81 * See irq_32.c. 82 */ 83 info->next_sp = (unsigned long *)*begin; 84 85 return true; 86 } 87 in_doublefault_stack(unsigned long * stack,struct stack_info * info)88 static bool in_doublefault_stack(unsigned long *stack, struct stack_info *info) 89 { 90 struct cpu_entry_area *cea = get_cpu_entry_area(raw_smp_processor_id()); 91 struct doublefault_stack *ss = &cea->doublefault_stack; 92 93 void *begin = ss->stack; 94 void *end = begin + sizeof(ss->stack); 95 96 if ((void *)stack < begin || (void *)stack >= end) 97 return false; 98 99 info->type = STACK_TYPE_EXCEPTION; 100 info->begin = begin; 101 info->end = end; 102 info->next_sp = (unsigned long *)this_cpu_read(cpu_tss_rw.x86_tss.sp); 103 104 return true; 105 } 106 107 get_stack_info(unsigned long * stack,struct task_struct * task,struct stack_info * info,unsigned long * visit_mask)108 int get_stack_info(unsigned long *stack, struct task_struct *task, 109 struct stack_info *info, unsigned long *visit_mask) 110 { 111 if (!stack) 112 goto unknown; 113 114 task = task ? : current; 115 116 if (in_task_stack(stack, task, info)) 117 goto recursion_check; 118 119 if (task != current) 120 goto unknown; 121 122 if (in_entry_stack(stack, info)) 123 goto recursion_check; 124 125 if (in_hardirq_stack(stack, info)) 126 goto recursion_check; 127 128 if (in_softirq_stack(stack, info)) 129 goto recursion_check; 130 131 if (in_doublefault_stack(stack, info)) 132 goto recursion_check; 133 134 goto unknown; 135 136 recursion_check: 137 /* 138 * Make sure we don't iterate through any given stack more than once. 139 * If it comes up a second time then there's something wrong going on: 140 * just break out and report an unknown stack type. 141 */ 142 if (visit_mask) { 143 if (*visit_mask & (1UL << info->type)) { 144 printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type); 145 goto unknown; 146 } 147 *visit_mask |= 1UL << info->type; 148 } 149 150 return 0; 151 152 unknown: 153 info->type = STACK_TYPE_UNKNOWN; 154 return -EINVAL; 155 } 156