[PATCH] base/class.c: prevent ooops due to insert/remove race

[Mark Lord <lkml@rtr.ca>]

While doing insert/remove (quickly) tests on USB, I managed to trigger
an Oops on 2.6.23.1 on the call to strlen() in make_class_name().

This patch prevents this oops.

There is still the larger problem of the overall race
that caused this in the first place, but much of the rest
of the code in class.c appears to also do NULL checks to
avoid Oops'ing, so this continues the tradition.

Signed-off-by:  Mark Lord <mlord@pobox.com>
---

Patch applies to both 2.6.24 and 2.6.23.

--- old/drivers/base/class.c	2007-11-28 22:54:59.000000000 -0500
+++ linux/drivers/base/class.c	2007-11-28 22:54:48.000000000 -0500
@@ -354,6 +354,8 @@
 	char *class_name;
 	int size;
 
+	if (!name)
+		return NULL;
 	size = strlen(name) + strlen(kobject_name(kobj)) + 2;
 
 	class_name = kmalloc(size, GFP_KERNEL);