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