Merge branch 'perf/urgent' into perf/core, to pick up latest fixes and refresh the tree

Signed-off-by: Ingo Molnar <mingo@kernel.org>

2 files changed, 20 insertions, 2 deletions

diff --git a/init/Kconfig b/init/Kconfig
index ee0f03b69d11..8514b25db21c 100644
--- a/init/Kconfig
+++ b/init/Kconfig
@@ -859,11 +859,14 @@ config CGROUP_BPF
 	  inet sockets.
 
 config CGROUP_DEBUG
-	bool "Example controller"
+	bool "Debug controller"
 	default n
+	depends on DEBUG_KERNEL
 	help
 	  This option enables a simple controller that exports
-	  debugging information about the cgroups framework.
+	  debugging information about the cgroups framework. This
+	  controller is for control cgroup debugging only. Its
+	  interfaces are not stable.
 
 	  Say N.
 
@@ -1545,6 +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
diff --git a/init/main.c b/init/main.c
index df58a416dd1d..052481fbe363 100644
--- a/init/main.c
+++ b/init/main.c
@@ -518,6 +518,7 @@ asmlinkage __visible void __init start_kernel(void)
 	/*
 	 * Set up the initial canary ASAP:
 	 */
+	add_latent_entropy();
 	boot_init_stack_canary();
 
 	cgroup_init_early();