Fix: NULL pointer dereference of THIS_MODULE with built-in modules

[lttng-modules.git] / wrapper / tracepoint.h

diff --git a/wrapper/tracepoint.h b/wrapper/tracepoint.h
index 798d785b1accc1ae2a703e509c6aa322aeb76860..780f9a86607adf55848a72f4b5c2c7fef3d2e9c4 100644 (file)
--- a/wrapper/tracepoint.h
+++ b/wrapper/tracepoint.h
@@ -25,6 +25,7 @@
 
 #include <linux/version.h>
 #include <linux/tracepoint.h>
+#include <linux/module.h>
 
 #if (LINUX_VERSION_CODE < KERNEL_VERSION(2,6,35))
 
@@ -36,9 +37,87 @@
 
 #define kabi_2635_tracepoint_probe_register tracepoint_probe_register
 #define kabi_2635_tracepoint_probe_unregister tracepoint_probe_unregister
-#define kabi_2635_tracepoint_probe_register_noupdate tracepoint_probe_register_noupdate
-#define kabi_2635_tracepoint_probe_unregister_noupdate tracepoint_probe_unregister_noupdate
 
 #endif /* HAVE_KABI_2635_TRACEPOINT */
 
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,15,0))
+
+#include <lttng-tracepoint.h>
+
+#define lttng_wrapper_tracepoint_probe_register lttng_tracepoint_probe_register
+#define lttng_wrapper_tracepoint_probe_unregister lttng_tracepoint_probe_unregister
+
+#else /* #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,15,0)) */
+
+#define lttng_wrapper_tracepoint_probe_register kabi_2635_tracepoint_probe_register
+#define lttng_wrapper_tracepoint_probe_unregister kabi_2635_tracepoint_probe_unregister
+
+static inline
+int lttng_tracepoint_init(void)
+{
+       return 0;
+}
+
+static inline
+void lttng_tracepoint_exit(void)
+{
+}
+
+#endif /* #else #if (LINUX_VERSION_CODE >= KERNEL_VERSION(3,15,0)) */
+
+#ifdef CONFIG_MODULE_SIG
+
+#include <linux/kallsyms.h>
+#include <wrapper/kallsyms.h>
+
+static inline
+int wrapper_tracepoint_module_notify(struct notifier_block *nb,
+               unsigned long val, struct module *mod)
+{
+       int (*tracepoint_module_notify_sym)(struct notifier_block *nb,
+                       unsigned long val, struct module *mod);
+
+       tracepoint_module_notify_sym =
+               (void *) kallsyms_lookup_funcptr("tracepoint_module_notify");
+       if (tracepoint_module_notify_sym) {
+               return tracepoint_module_notify_sym(nb, val, mod);
+       } else {
+               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");
+               return -ENOSYS;
+       }
+}
+
+#endif /* CONFIG_MODULE_SIG */
+
+#if defined(CONFIG_MODULE_SIG) && defined(MODULE)
+
+static inline
+int wrapper_lttng_fixup_sig(struct module *mod)
+{
+       int ret = 0;
+
+       /*
+        * This is for module.c confusing force loaded modules with
+        * unsigned modules.
+        */
+       if (!THIS_MODULE->sig_ok &&
+                       THIS_MODULE->taints & (1U << TAINT_FORCED_MODULE)) {
+               THIS_MODULE->taints &= ~(1U << TAINT_FORCED_MODULE);
+               ret = wrapper_tracepoint_module_notify(NULL,
+                               MODULE_STATE_COMING, mod);
+               THIS_MODULE->taints |= (1U << TAINT_FORCED_MODULE);
+       }
+       return ret;
+}
+
+#else /* #if defined(CONFIG_MODULE_SIG) && defined(MODULE) */
+
+static inline
+int wrapper_lttng_fixup_sig(struct module *mod)
+{
+       return 0;
+}
+
+#endif /*#else #if defined(CONFIG_MODULE_SIG) && defined(MODULE) */
+
 #endif /* _LTTNG_WRAPPER_TRACEPOINT_H */