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1/*
2 * Copyright (C) 1991, 1992 Linus Torvalds
3 * Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
4 */
5#include <linux/kallsyms.h>
6#include <linux/kprobes.h>
7#include <linux/uaccess.h>
8#include <linux/hardirq.h>
9#include <linux/kdebug.h>
10#include <linux/module.h>
11#include <linux/ptrace.h>
12#include <linux/kexec.h>
13#include <linux/sysfs.h>
14#include <linux/bug.h>
15#include <linux/nmi.h>
16
17#include <asm/stacktrace.h>
18
19
20#define N_EXCEPTION_STACKS_END \
21 (N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2)
22
23static char x86_stack_ids[][8] = {
24 [ DEBUG_STACK-1 ] = "#DB",
25 [ NMI_STACK-1 ] = "NMI",
26 [ DOUBLEFAULT_STACK-1 ] = "#DF",
27 [ STACKFAULT_STACK-1 ] = "#SS",
28 [ MCE_STACK-1 ] = "#MC",
29#if DEBUG_STKSZ > EXCEPTION_STKSZ
30 [ N_EXCEPTION_STACKS ...
31 N_EXCEPTION_STACKS_END ] = "#DB[?]"
32#endif
33};
34
35static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
36 unsigned *usedp, char **idp)
37{
38 unsigned k;
39
40 /*
41 * Iterate over all exception stacks, and figure out whether
42 * 'stack' is in one of them:
43 */
44 for (k = 0; k < N_EXCEPTION_STACKS; k++) {
45 unsigned long end = per_cpu(orig_ist, cpu).ist[k];
46 /*
47 * Is 'stack' above this exception frame's end?
48 * If yes then skip to the next frame.
49 */
50 if (stack >= end)
51 continue;
52 /*
53 * Is 'stack' above this exception frame's start address?
54 * If yes then we found the right frame.
55 */
56 if (stack >= end - EXCEPTION_STKSZ) {
57 /*
58 * Make sure we only iterate through an exception
59 * stack once. If it comes up for the second time
60 * then there's something wrong going on - just
61 * break out and return NULL:
62 */
63 if (*usedp & (1U << k))
64 break;
65 *usedp |= 1U << k;
66 *idp = x86_stack_ids[k];
67 return (unsigned long *)end;
68 }
69 /*
70 * If this is a debug stack, and if it has a larger size than
71 * the usual exception stacks, then 'stack' might still
72 * be within the lower portion of the debug stack:
73 */
74#if DEBUG_STKSZ > EXCEPTION_STKSZ
75 if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
76 unsigned j = N_EXCEPTION_STACKS - 1;
77
78 /*
79 * Black magic. A large debug stack is composed of
80 * multiple exception stack entries, which we
81 * iterate through now. Dont look:
82 */
83 do {
84 ++j;
85 end -= EXCEPTION_STKSZ;
86 x86_stack_ids[j][4] = '1' +
87 (j - N_EXCEPTION_STACKS);
88 } while (stack < end - EXCEPTION_STKSZ);
89 if (*usedp & (1U << j))
90 break;
91 *usedp |= 1U << j;
92 *idp = x86_stack_ids[j];
93 return (unsigned long *)end;
94 }
95#endif
96 }
97 return NULL;
98}
99
100static inline int
101in_irq_stack(unsigned long *stack, unsigned long *irq_stack,
102 unsigned long *irq_stack_end)
103{
104 return (stack >= irq_stack && stack < irq_stack_end);
105}
106
107/*
108 * x86-64 can have up to three kernel stacks:
109 * process stack
110 * interrupt stack
111 * severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
112 */
113
114void dump_trace(struct task_struct *task, struct pt_regs *regs,
115 unsigned long *stack, unsigned long bp,
116 const struct stacktrace_ops *ops, void *data)
117{
118 const unsigned cpu = get_cpu();
119 unsigned long *irq_stack_end =
120 (unsigned long *)per_cpu(irq_stack_ptr, cpu);
121 unsigned used = 0;
122 struct thread_info *tinfo;
123 int graph = 0;
124 unsigned long dummy;
125
126 if (!task)
127 task = current;
128
129 if (!stack) {
130 if (regs)
131 stack = (unsigned long *)regs->sp;
132 else if (task != current)
133 stack = (unsigned long *)task->thread.sp;
134 else
135 stack = &dummy;
136 }
137
138 if (!bp)
139 bp = stack_frame(task, regs);
140 /*
141 * Print function call entries in all stacks, starting at the
142 * current stack address. If the stacks consist of nested
143 * exceptions
144 */
145 tinfo = task_thread_info(task);
146 for (;;) {
147 char *id;
148 unsigned long *estack_end;
149 estack_end = in_exception_stack(cpu, (unsigned long)stack,
150 &used, &id);
151
152 if (estack_end) {
153 if (ops->stack(data, id) < 0)
154 break;
155
156 bp = ops->walk_stack(tinfo, stack, bp, ops,
157 data, estack_end, &graph);
158 ops->stack(data, "<EOE>");
159 /*
160 * We link to the next stack via the
161 * second-to-last pointer (index -2 to end) in the
162 * exception stack:
163 */
164 stack = (unsigned long *) estack_end[-2];
165 continue;
166 }
167 if (irq_stack_end) {
168 unsigned long *irq_stack;
169 irq_stack = irq_stack_end -
170 (IRQ_STACK_SIZE - 64) / sizeof(*irq_stack);
171
172 if (in_irq_stack(stack, irq_stack, irq_stack_end)) {
173 if (ops->stack(data, "IRQ") < 0)
174 break;
175 bp = ops->walk_stack(tinfo, stack, bp,
176 ops, data, irq_stack_end, &graph);
177 /*
178 * We link to the next stack (which would be
179 * the process stack normally) the last
180 * pointer (index -1 to end) in the IRQ stack:
181 */
182 stack = (unsigned long *) (irq_stack_end[-1]);
183 irq_stack_end = NULL;
184 ops->stack(data, "EOI");
185 continue;
186 }
187 }
188 break;
189 }
190
191 /*
192 * This handles the process stack:
193 */
194 bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
195 put_cpu();
196}
197EXPORT_SYMBOL(dump_trace);
198
199void
200show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
201 unsigned long *sp, unsigned long bp, char *log_lvl)
202{
203 unsigned long *irq_stack_end;
204 unsigned long *irq_stack;
205 unsigned long *stack;
206 int cpu;
207 int i;
208
209 preempt_disable();
210 cpu = smp_processor_id();
211
212 irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
213 irq_stack = (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);
214
215 /*
216 * Debugging aid: "show_stack(NULL, NULL);" prints the
217 * back trace for this cpu:
218 */
219 if (sp == NULL) {
220 if (task)
221 sp = (unsigned long *)task->thread.sp;
222 else
223 sp = (unsigned long *)&sp;
224 }
225
226 stack = sp;
227 for (i = 0; i < kstack_depth_to_print; i++) {
228 if (stack >= irq_stack && stack <= irq_stack_end) {
229 if (stack == irq_stack_end) {
230 stack = (unsigned long *) (irq_stack_end[-1]);
231 printk(KERN_CONT " <EOI> ");
232 }
233 } else {
234 if (((long) stack & (THREAD_SIZE-1)) == 0)
235 break;
236 }
237 if (i && ((i % STACKSLOTS_PER_LINE) == 0))
238 printk(KERN_CONT "\n");
239 printk(KERN_CONT " %016lx", *stack++);
240 touch_nmi_watchdog();
241 }
242 preempt_enable();
243
244 printk(KERN_CONT "\n");
245 show_trace_log_lvl(task, regs, sp, bp, log_lvl);
246}
247
248void show_regs(struct pt_regs *regs)
249{
250 int i;
251 unsigned long sp;
252 const int cpu = smp_processor_id();
253 struct task_struct *cur = current;
254
255 sp = regs->sp;
256 printk("CPU %d ", cpu);
257 print_modules();
258 __show_regs(regs, 1);
259 printk("Process %s (pid: %d, threadinfo %p, task %p)\n",
260 cur->comm, cur->pid, task_thread_info(cur), cur);
261
262 /*
263 * When in-kernel, we also print out the stack and code at the
264 * time of the fault..
265 */
266 if (!user_mode(regs)) {
267 unsigned int code_prologue = code_bytes * 43 / 64;
268 unsigned int code_len = code_bytes;
269 unsigned char c;
270 u8 *ip;
271
272 printk(KERN_DEFAULT "Stack:\n");
273 show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
274 0, KERN_DEFAULT);
275
276 printk(KERN_DEFAULT "Code: ");
277
278 ip = (u8 *)regs->ip - code_prologue;
279 if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
280 /* try starting at IP */
281 ip = (u8 *)regs->ip;
282 code_len = code_len - code_prologue + 1;
283 }
284 for (i = 0; i < code_len; i++, ip++) {
285 if (ip < (u8 *)PAGE_OFFSET ||
286 probe_kernel_address(ip, c)) {
287 printk(KERN_CONT " Bad RIP value.");
288 break;
289 }
290 if (ip == (u8 *)regs->ip)
291 printk(KERN_CONT "<%02x> ", c);
292 else
293 printk(KERN_CONT "%02x ", c);
294 }
295 }
296 printk(KERN_CONT "\n");
297}
298
299int is_valid_bugaddr(unsigned long ip)
300{
301 unsigned short ud2;
302
303 if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
304 return 0;
305
306 return ud2 == 0x0b0f;
307}
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
21static 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",
26};
27
28static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
29 [0 ... N_EXCEPTION_STACKS - 1] = EXCEPTION_STKSZ,
30 [DEBUG_STACK - 1] = DEBUG_STKSZ
31};
32
33const char *stack_type_name(enum stack_type type)
34{
35 BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
36
37 if (type == STACK_TYPE_IRQ)
38 return "IRQ";
39
40 if (type == STACK_TYPE_ENTRY) {
41 /*
42 * On 64-bit, we have a generic entry stack that we
43 * use for all the kernel entry points, including
44 * SYSENTER.
45 */
46 return "ENTRY_TRAMPOLINE";
47 }
48
49 if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)
50 return exception_stack_names[type - STACK_TYPE_EXCEPTION];
51
52 return NULL;
53}
54
55static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
56{
57 unsigned long *begin, *end;
58 struct pt_regs *regs;
59 unsigned k;
60
61 BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);
62
63 for (k = 0; k < N_EXCEPTION_STACKS; k++) {
64 end = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k];
65 begin = end - (exception_stack_sizes[k] / sizeof(long));
66 regs = (struct pt_regs *)end - 1;
67
68 if (stack <= begin || stack >= end)
69 continue;
70
71 info->type = STACK_TYPE_EXCEPTION + k;
72 info->begin = begin;
73 info->end = end;
74 info->next_sp = (unsigned long *)regs->sp;
75
76 return true;
77 }
78
79 return false;
80}
81
82static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
83{
84 unsigned long *end = (unsigned long *)this_cpu_read(irq_stack_ptr);
85 unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));
86
87 /*
88 * This is a software stack, so 'end' can be a valid stack pointer.
89 * It just means the stack is empty.
90 */
91 if (stack <= begin || stack > end)
92 return false;
93
94 info->type = STACK_TYPE_IRQ;
95 info->begin = begin;
96 info->end = end;
97
98 /*
99 * The next stack pointer is the first thing pushed by the entry code
100 * after switching to the irq stack.
101 */
102 info->next_sp = (unsigned long *)*(end - 1);
103
104 return true;
105}
106
107int get_stack_info(unsigned long *stack, struct task_struct *task,
108 struct stack_info *info, unsigned long *visit_mask)
109{
110 if (!stack)
111 goto unknown;
112
113 task = task ? : current;
114
115 if (in_task_stack(stack, task, info))
116 goto recursion_check;
117
118 if (task != current)
119 goto unknown;
120
121 if (in_exception_stack(stack, info))
122 goto recursion_check;
123
124 if (in_irq_stack(stack, info))
125 goto recursion_check;
126
127 if (in_entry_stack(stack, info))
128 goto recursion_check;
129
130 goto unknown;
131
132recursion_check:
133 /*
134 * Make sure we don't iterate through any given stack more than once.
135 * If it comes up a second time then there's something wrong going on:
136 * just break out and report an unknown stack type.
137 */
138 if (visit_mask) {
139 if (*visit_mask & (1UL << info->type)) {
140 printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
141 goto unknown;
142 }
143 *visit_mask |= 1UL << info->type;
144 }
145
146 return 0;
147
148unknown:
149 info->type = STACK_TYPE_UNKNOWN;
150 return -EINVAL;
151}