module: workaround duplicate section names

The root cause is a duplicate section name (.text); is this legal?
[ Amerigo Wang: "AFAIK, yes." ]

However, there's a problem with commit
6d76013381ed28979cd122eb4b249a88b5e384fa in that if you fail to allocate
a mod->sect_attrs (in this case it's null because of the duplication),
it still gets used without checking in add_notes_attrs()

This should fix it

[ This patch leaves other problems, particularly the sections directory,
  but recent parisc toolchains seem to produce these modules and this
  prevents a crash and is a minimal change -- RR ]

Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Tested-by: Helge Deller <deller@gmx.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

kernel/module.c

@@ -2355,7 +2355,8 @@ static noinline struct module *load_module(void __user *umod,
 	if (err < 0)
 		goto unlink;
 	add_sect_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
-	add_notes_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
+	if (mod->sect_attrs)
+		add_notes_attrs(mod, hdr->e_shnum, secstrings, sechdrs);
 
 	/* Get rid of temporary copy */
 	vfree(hdr);