slub: fix panic with DISCONTIGMEM

commit 4a5fa3590f09999f6db41bc386bce40848fa9f63 upstream.

Slub makes assumptions about page_to_nid() which are violated by
DISCONTIGMEM and !NUMA.  This violation results in a panic because
page_to_nid() can be non-zero for pages in the discontiguous ranges and
this leads to a null return by get_node().  The assertion by the
maintainer is that DISCONTIGMEM should only be allowed when NUMA is also
defined.  However, at least six architectures: alpha, ia64, m32r, m68k,
mips, parisc violate this.  The panic is a regression against slab, so
just mark slub broken in the problem configuration to prevent users
reporting these panics.

Acked-by: David Rientjes <rientjes@google.com>
Acked-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/init/Kconfig b/init/Kconfig
index d95ca7cd5d45f092fe33e175a577e0a94675c549..3e45a9b7c59fe4f3519e3074222f4944fe5e22ef 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1070,6 +1070,7 @@ config SLAB
          per cpu and per node queues.
 
 config SLUB
+       depends on BROKEN || NUMA || !DISCONTIGMEM
        bool "SLUB (Unqueued Allocator)"
        help
           SLUB is a slab allocator that minimizes cache line usage