commit 5479c78ac6f688ea5ea8c49b44cf90ea87b63931
author Cyrill Gorcunov <gorcunov@openvz.org> Sun Nov 25 01:17:13 2012 +0400
committer Tejun Heo <tj@kernel.org> Sun Dec 02 06:23:04 2012 -0800
tree 449331a4649fb1dd019509d6c5a7ae71bbc05157
parent b4916cb17c261a6043bcb2a98d0d6512497a7cf8

mm, percpu: Make sure percpu_alloc early parameter has an argument

Otherwise we are getting a nil dereference if percpu_alloc kernel boot
argument is specified without value.

 | [    0.000000] BUG: unable to handle kernel NULL pointer dereference at           (null)
 | [    0.000000] IP: [<ffffffff81391360>] strcmp+0x10/0x30

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

mm/percpu.c

diff --git a/mm/percpu.c b/mm/percpu.c
index ec25896..8c8e08f 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -1380,6 +1380,9 @@
 
 static int __init percpu_alloc_setup(char *str)
 {
+	if (!str)
+		return -EINVAL;
+
 	if (0)
 		/* nada */;
 #ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK