| Andrew Scull | b4b6d4a | 2019-01-02 15:54:55 +0000 | [diff] [blame] | 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 | } |