Fix: NULL pointer dereference of THIS_MODULE with built-in modules
[deliverable/lttng-modules.git] / wrapper / tracepoint.h
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1#ifndef _LTTNG_WRAPPER_TRACEPOINT_H
2#define _LTTNG_WRAPPER_TRACEPOINT_H
3
4/*
5 * wrapper/tracepoint.h
6 *
7 * wrapper around DECLARE_EVENT_CLASS.
8 *
9 * Copyright (C) 2011-2012 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
10 *
11 * This library is free software; you can redistribute it and/or
12 * modify it under the terms of the GNU Lesser General Public
13 * License as published by the Free Software Foundation; only
14 * version 2.1 of the License.
15 *
16 * This library is distributed in the hope that it will be useful,
17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
19 * Lesser General Public License for more details.
20 *
21 * You should have received a copy of the GNU Lesser General Public
22 * License along with this library; if not, write to the Free Software
23 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 */
25
26#include <linux/version.h>
27#include <linux/tracepoint.h>
dd8d5afb 28#include <linux/module.h>
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29
30#if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,35))
31
32#define DECLARE_EVENT_CLASS(name, proto, args, tstruct, assign, print)
33
34#endif
35
36#ifndef HAVE_KABI_2635_TRACEPOINT
37
38#define kabi_2635_tracepoint_probe_register tracepoint_probe_register
39#define kabi_2635_tracepoint_probe_unregister tracepoint_probe_unregister
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40
41#endif /* HAVE_KABI_2635_TRACEPOINT */
42
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43#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,15,0))
44
5a2f5e92 45#include <lttng-tracepoint.h>
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46
47#define lttng_wrapper_tracepoint_probe_register lttng_tracepoint_probe_register
48#define lttng_wrapper_tracepoint_probe_unregister lttng_tracepoint_probe_unregister
49
50#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,15,0)) */
51
52#define lttng_wrapper_tracepoint_probe_register kabi_2635_tracepoint_probe_register
53#define lttng_wrapper_tracepoint_probe_unregister kabi_2635_tracepoint_probe_unregister
54
55static inline
56int lttng_tracepoint_init(void)
57{
58 return 0;
59}
60
61static inline
62void lttng_tracepoint_exit(void)
63{
64}
65
66#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,15,0)) */
67
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68#ifdef CONFIG_MODULE_SIG
69
70#include <linux/kallsyms.h>
5a2f5e92 71#include <wrapper/kallsyms.h>
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72
73static inline
74int wrapper_tracepoint_module_notify(struct notifier_block *nb,
75 unsigned long val, struct module *mod)
76{
77 int (*tracepoint_module_notify_sym)(struct notifier_block *nb,
78 unsigned long val, struct module *mod);
79
80 tracepoint_module_notify_sym =
81 (void *) kallsyms_lookup_funcptr("tracepoint_module_notify");
82 if (tracepoint_module_notify_sym) {
83 return tracepoint_module_notify_sym(nb, val, mod);
84 } else {
e36de50d 85 printk_once(KERN_WARNING "LTTng: tracepoint_module_notify symbol lookup failed. It probably means you kernel don't need this work-around. Please consider upgrading LTTng modules to make this warning go away.\n");
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86 return -ENOSYS;
87 }
88}
89
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90#endif /* CONFIG_MODULE_SIG */
91
92#if defined(CONFIG_MODULE_SIG) && defined(MODULE)
93
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94static inline
95int wrapper_lttng_fixup_sig(struct module *mod)
96{
97 int ret = 0;
98
99 /*
100 * This is for module.c confusing force loaded modules with
101 * unsigned modules.
102 */
103 if (!THIS_MODULE->sig_ok &&
104 THIS_MODULE->taints & (1U << TAINT_FORCED_MODULE)) {
105 THIS_MODULE->taints &= ~(1U << TAINT_FORCED_MODULE);
106 ret = wrapper_tracepoint_module_notify(NULL,
107 MODULE_STATE_COMING, mod);
108 THIS_MODULE->taints |= (1U << TAINT_FORCED_MODULE);
109 }
110 return ret;
111}
112
a9799a51 113#else /* #if defined(CONFIG_MODULE_SIG) && defined(MODULE) */
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114
115static inline
116int wrapper_lttng_fixup_sig(struct module *mod)
117{
118 return 0;
119}
120
a9799a51 121#endif /*#else #if defined(CONFIG_MODULE_SIG) && defined(MODULE) */
dd8d5afb 122
3a523f5b 123#endif /* _LTTNG_WRAPPER_TRACEPOINT_H */
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