From: Francis Deslauriers <francis.deslauriers@efficios.com>
Date: Wed, 17 May 2017 21:09:12 +0000 (-0400)
Subject: Fix: NULL pointer dereference of THIS_MODULE with built-in modules
X-Git-Tag: v2.11.0-rc1~129
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=0147ae6413de42a6f254a17793414c7f25e4f28a;p=lttng-modules.git

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

THIS MODULE is defined to 0 when a module is built-in the kernel [1].
This caused NULL pointer dereference when booting a kernel with the
lttng-modules built-in.
To fix this issue, add #if guard around the wrapper_lttng_fixup_sig
function checking if the MODULE macro is defined to confirm that this
piece of code will end up in a module and not in the kernel itself.

[1]: linux/include/linux/export.h:32
Fixes: #1107

Signed-off-by: Francis Deslauriers <francis.deslauriers@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/wrapper/tracepoint.h b/wrapper/tracepoint.h
index 367cdf42..780f9a86 100644
--- a/wrapper/tracepoint.h
+++ b/wrapper/tracepoint.h
@@ -87,6 +87,10 @@ int wrapper_tracepoint_module_notify(struct notifier_block *nb,
 	}
 }
 
+#endif /* CONFIG_MODULE_SIG */
+
+#if defined(CONFIG_MODULE_SIG) && defined(MODULE)
+
 static inline
 int wrapper_lttng_fixup_sig(struct module *mod)
 {
@@ -106,7 +110,7 @@ int wrapper_lttng_fixup_sig(struct module *mod)
 	return ret;
 }
 
-#else /* CONFIG_MODULE_SIG */
+#else /* #if defined(CONFIG_MODULE_SIG) && defined(MODULE) */
 
 static inline
 int wrapper_lttng_fixup_sig(struct module *mod)
@@ -114,6 +118,6 @@ int wrapper_lttng_fixup_sig(struct module *mod)
 	return 0;
 }
 
-#endif /* #else CONFIG_MODULE_SIG */
+#endif /*#else #if defined(CONFIG_MODULE_SIG) && defined(MODULE) */
 
 #endif /* _LTTNG_WRAPPER_TRACEPOINT_H */