mm: allow slab_nomerge to be set at build time

[mirror_ubuntu-artful-kernel.git] / init / Kconfig

diff --git a/init/Kconfig b/init/Kconfig
index b0fcbb2c6f56a193c38542baa03f0145518cd0c1..8514b25db21c6bb6928a6944cc6867ae9414321c 100644 (file)
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -1548,6 +1548,20 @@ config SLOB
 
 endchoice
 
+config SLAB_MERGE_DEFAULT
+       bool "Allow slab caches to be merged"
+       default y
+       help
+         For reduced kernel memory fragmentation, slab caches can be
+         merged when they share the same size and other characteristics.
+         This carries a risk of kernel heap overflows being able to
+         overwrite objects from merged caches (and more easily control
+         cache layout), which makes such heap attacks easier to exploit
+         by attackers. By keeping caches unmerged, these kinds of exploits
+         can usually only damage objects in the same cache. To disable
+         merging at runtime, "slab_nomerge" can be passed on the kernel
+         command line.
+
 config SLAB_FREELIST_RANDOM
        default n
        depends on SLAB || SLUB