1// SPDX-License-Identifier: GPL-2.0
 2/*
 3 * Stack trace management functions
 4 *
 5 *  Copyright IBM Corp. 2006
 6 *  Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
 7 */
 8
 
 9#include <linux/stacktrace.h>
10#include <asm/stacktrace.h>
11#include <asm/unwind.h>
12#include <asm/kprobes.h>
13
14void arch_stack_walk(stack_trace_consume_fn consume_entry, void *cookie,
15		     struct task_struct *task, struct pt_regs *regs)
16{
17	struct unwind_state state;
18	unsigned long addr;
19
20	unwind_for_each_frame(&state, task, regs, 0) {
21		addr = unwind_get_return_address(&state);
22		if (!addr || !consume_entry(cookie, addr, false))
23			break;
24	}
 
 
 
 
 
25}
26
27/*
28 * This function returns an error if it detects any unreliable features of the
29 * stack.  Otherwise it guarantees that the stack trace is reliable.
30 *
31 * If the task is not 'current', the caller *must* ensure the task is inactive.
32 */
33int arch_stack_walk_reliable(stack_trace_consume_fn consume_entry,
34			     void *cookie, struct task_struct *task)
35{
36	struct unwind_state state;
37	unsigned long addr;
38
39	unwind_for_each_frame(&state, task, NULL, 0) {
40		if (state.stack_info.type != STACK_TYPE_TASK)
41			return -EINVAL;
42
43		if (state.regs)
44			return -EINVAL;
45
46		addr = unwind_get_return_address(&state);
47		if (!addr)
48			return -EINVAL;
49
50#ifdef CONFIG_KPROBES
51		/*
52		 * Mark stacktraces with kretprobed functions on them
53		 * as unreliable.
54		 */
55		if (state.ip == (unsigned long)kretprobe_trampoline)
56			return -EINVAL;
57#endif
58
59		if (!consume_entry(cookie, addr, false))
60			return -EINVAL;
61	}
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
62
63	/* Check for stack corruption */
64	if (unwind_error(&state))
65		return -EINVAL;
66	return 0;
67}

 
 1/*
 2 * Stack trace management functions
 3 *
 4 *  Copyright IBM Corp. 2006
 5 *  Author(s): Heiko Carstens <heiko.carstens@de.ibm.com>
 6 */
 7
 8#include <linux/sched.h>
 9#include <linux/stacktrace.h>
10#include <linux/kallsyms.h>
11#include <linux/module.h>
12
13static int __save_address(void *data, unsigned long address, int nosched)
14{
15	struct stack_trace *trace = data;
16
17	if (nosched && in_sched_functions(address))
18		return 0;
19	if (trace->skip > 0) {
20		trace->skip--;
21		return 0;
 
 
22	}
23	if (trace->nr_entries < trace->max_entries) {
24		trace->entries[trace->nr_entries++] = address;
25		return 0;
26	}
27	return 1;
28}
29
30static int save_address(void *data, unsigned long address, int reliable)
31{
32	return __save_address(data, address, 0);
33}
34
35static int save_address_nosched(void *data, unsigned long address, int reliable)
 
 
36{
37	return __save_address(data, address, 1);
38}
39
40void save_stack_trace(struct stack_trace *trace)
41{
42	unsigned long sp;
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
43
44	sp = current_stack_pointer();
45	dump_trace(save_address, trace, NULL, sp);
46	if (trace->nr_entries < trace->max_entries)
47		trace->entries[trace->nr_entries++] = ULONG_MAX;
48}
49EXPORT_SYMBOL_GPL(save_stack_trace);
50
51void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
52{
53	unsigned long sp;
54
55	sp = tsk->thread.ksp;
56	if (tsk == current)
57		sp = current_stack_pointer();
58	dump_trace(save_address_nosched, trace, tsk, sp);
59	if (trace->nr_entries < trace->max_entries)
60		trace->entries[trace->nr_entries++] = ULONG_MAX;
61}
62EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
63
64void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
65{
66	unsigned long sp;
67
68	sp = kernel_stack_pointer(regs);
69	dump_trace(save_address, trace, NULL, sp);
70	if (trace->nr_entries < trace->max_entries)
71		trace->entries[trace->nr_entries++] = ULONG_MAX;
72}
73EXPORT_SYMBOL_GPL(save_stack_trace_regs);