From: Juerg Haefliger <juerg.haefliger@hpe.com>
Date: Thu, 19 Jan 2017 10:40:13 +0000 (+0100)
Subject: lkdtm: Fix Oops when unloading the module
X-Git-Tag: v4.11-rc1~118^2~96
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=9ba60573638e2006170ebcc5489fb1e068afbc8f;p=karo-tx-linux.git

lkdtm: Fix Oops when unloading the module

No jprobe is registered when the module is loaded without specifying a
crashpoint that uses a jprobe. At the moment, we unconditionally try to
unregister the jprobe on module unload which results in an Oops. Add a
check to fix this.

Signed-off-by: Juerg Haefliger <juerg.haefliger@hpe.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c
index 7eeb71a75549..4d44084071d8 100644
--- a/drivers/misc/lkdtm_core.c
+++ b/drivers/misc/lkdtm_core.c
@@ -535,7 +535,9 @@ static void __exit lkdtm_module_exit(void)
 	/* Handle test-specific clean-up. */
 	lkdtm_usercopy_exit();
 
-	unregister_jprobe(lkdtm_jprobe);
+	if (lkdtm_jprobe != NULL)
+		unregister_jprobe(lkdtm_jprobe);
+
 	pr_info("Crash point unregistered\n");
 }