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: C0P2-H0.0--20200415~7283
X-Git-Url: https://git.somdevices.com/?a=commitdiff_plain;h=c593091cfc1bee31b56b555c83dc5f0ed715d7ed;p=linux.git

lkdtm: Fix Oops when unloading the module


[ Upstream commit 9ba60573638e2006170ebcc5489fb1e068afbc8f ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/drivers/misc/lkdtm_core.c b/drivers/misc/lkdtm_core.c
index f9154b8d67f6..b2989f2d3126 100644
--- a/drivers/misc/lkdtm_core.c
+++ b/drivers/misc/lkdtm_core.c
@@ -533,7 +533,9 @@ 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");
 }