Merge branch 'akpm' (patches from Andrew)

Merge misc updates from Andrew Morton:

 - a few MM hotfixes

 - kthread, tools, scripts, ntfs and ocfs2

 - some of MM

Subsystems affected by this patch series: kthread, tools, scripts, ntfs,
ocfs2 and mm (hofixes, pagealloc, slab-generic, slab, slub, kcsan,
debug, pagecache, gup, swap, shmem, memcg, pagemap, mremap, mincore,
sparsemem, vmalloc, kasan, pagealloc, hugetlb and vmscan).

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (162 commits)
  mm: vmscan: consistent update to pgrefill
  mm/vmscan.c: fix typo
  khugepaged: khugepaged_test_exit() check mmget_still_valid()
  khugepaged: retract_page_tables() remember to test exit
  khugepaged: collapse_pte_mapped_thp() protect the pmd lock
  khugepaged: collapse_pte_mapped_thp() flush the right range
  mm/hugetlb: fix calculation of adjust_range_if_pmd_sharing_possible
  mm: thp: replace HTTP links with HTTPS ones
  mm/page_alloc: fix memalloc_nocma_{save/restore} APIs
  mm/page_alloc.c: skip setting nodemask when we are in interrupt
  mm/page_alloc: fallbacks at most has 3 elements
  mm/page_alloc: silence a KASAN false positive
  mm/page_alloc.c: remove unnecessary end_bitidx for [set|get]_pfnblock_flags_mask()
  mm/page_alloc.c: simplify pageblock bitmap access
  mm/page_alloc.c: extract the common part in pfn_to_bitidx()
  mm/page_alloc.c: replace the definition of NR_MIGRATETYPE_BITS with PB_migratetype_bits
  mm/shuffle: remove dynamic reconfiguration
  mm/memory_hotplug: document why shuffle_zone() is relevant
  mm/page_alloc: remove nr_free_pagecache_pages()
  mm: remove vm_total_pages
  ...

1 files changed, 23 insertions, 16 deletions

diff --git a/lib/Kconfig.kasan b/lib/Kconfig.kasan
index 34b84bcbd3d9..047b53dbfd58 100644
--- a/lib/Kconfig.kasan
+++ b/lib/Kconfig.kasan
@@ -18,7 +18,7 @@ config CC_HAS_KASAN_SW_TAGS
 config CC_HAS_WORKING_NOSANITIZE_ADDRESS
 	def_bool !CC_IS_GCC || GCC_VERSION >= 80300
 
-config KASAN
+menuconfig KASAN
 	bool "KASAN: runtime memory debugger"
 	depends on (HAVE_ARCH_KASAN && CC_HAS_KASAN_GENERIC) || \
 		   (HAVE_ARCH_KASAN_SW_TAGS && CC_HAS_KASAN_SW_TAGS)
@@ -29,9 +29,10 @@ config KASAN
 	  designed to find out-of-bounds accesses and use-after-free bugs.
 	  See Documentation/dev-tools/kasan.rst for details.
 
+if KASAN
+
 choice
 	prompt "KASAN mode"
-	depends on KASAN
 	default KASAN_GENERIC
 	help
 	  KASAN has two modes: generic KASAN (similar to userspace ASan,
@@ -39,6 +40,7 @@ choice
 	  software tag-based KASAN (a version based on software memory
 	  tagging, arm64 only, similar to userspace HWASan, enabled with
 	  CONFIG_KASAN_SW_TAGS).
+
 	  Both generic and tag-based KASAN are strictly debugging features.
 
 config KASAN_GENERIC
@@ -50,16 +52,18 @@ config KASAN_GENERIC
 	select STACKDEPOT
 	help
 	  Enables generic KASAN mode.
-	  Supported in both GCC and Clang. With GCC it requires version 4.9.2
-	  or later for basic support and version 5.0 or later for detection of
-	  out-of-bounds accesses for stack and global variables and for inline
-	  instrumentation mode (CONFIG_KASAN_INLINE). With Clang it requires
-	  version 3.7.0 or later and it doesn't support detection of
-	  out-of-bounds accesses for global variables yet.
+
+	  This mode is supported in both GCC and Clang. With GCC it requires
+	  version 8.3.0 or later. With Clang it requires version 7.0.0 or
+	  later, but detection of out-of-bounds accesses for global variables
+	  is supported only since Clang 11.
+
 	  This mode consumes about 1/8th of available memory at kernel start
 	  and introduces an overhead of ~x1.5 for the rest of the allocations.
 	  The performance slowdown is ~x3.
+
 	  For better error detection enable CONFIG_STACKTRACE.
+
 	  Currently CONFIG_KASAN_GENERIC doesn't work with CONFIG_DEBUG_SLAB
 	  (the resulting kernel does not boot).
 
@@ -72,15 +76,19 @@ config KASAN_SW_TAGS
 	select STACKDEPOT
 	help
 	  Enables software tag-based KASAN mode.
+
 	  This mode requires Top Byte Ignore support by the CPU and therefore
-	  is only supported for arm64.
-	  This mode requires Clang version 7.0.0 or later.
+	  is only supported for arm64. This mode requires Clang version 7.0.0
+	  or later.
+
 	  This mode consumes about 1/16th of available memory at kernel start
 	  and introduces an overhead of ~20% for the rest of the allocations.
 	  This mode may potentially introduce problems relating to pointer
 	  casting and comparison, as it embeds tags into the top byte of each
 	  pointer.
+
 	  For better error detection enable CONFIG_STACKTRACE.
+
 	  Currently CONFIG_KASAN_SW_TAGS doesn't work with CONFIG_DEBUG_SLAB
 	  (the resulting kernel does not boot).
 
@@ -88,7 +96,6 @@ endchoice
 
 choice
 	prompt "Instrumentation type"
-	depends on KASAN
 	default KASAN_OUTLINE
 
 config KASAN_OUTLINE
@@ -107,13 +114,11 @@ config KASAN_INLINE
 	  memory accesses. This is faster than outline (in some workloads
 	  it gives about x2 boost over outline instrumentation), but
 	  make kernel's .text size much bigger.
-	  For CONFIG_KASAN_GENERIC this requires GCC 5.0 or later.
 
 endchoice
 
 config KASAN_STACK_ENABLE
 	bool "Enable stack instrumentation (unsafe)" if CC_IS_CLANG && !COMPILE_TEST
-	depends on KASAN
 	help
 	  The LLVM stack address sanitizer has a know problem that
 	  causes excessive stack usage in a lot of functions, see
@@ -134,7 +139,7 @@ config KASAN_STACK
 
 config KASAN_S390_4_LEVEL_PAGING
 	bool "KASan: use 4-level paging"
-	depends on KASAN && S390
+	depends on S390
 	help
 	  Compiling the kernel with KASan disables automatic 3-level vs
 	  4-level paging selection. 3-level paging is used by default (up
@@ -151,7 +156,7 @@ config KASAN_SW_TAGS_IDENTIFY
 
 config KASAN_VMALLOC
 	bool "Back mappings in vmalloc space with real shadow memory"
-	depends on KASAN && HAVE_ARCH_KASAN_VMALLOC
+	depends on HAVE_ARCH_KASAN_VMALLOC
 	help
 	  By default, the shadow region for vmalloc space is the read-only
 	  zero page. This means that KASAN cannot detect errors involving
@@ -164,8 +169,10 @@ config KASAN_VMALLOC
 
 config TEST_KASAN
 	tristate "Module for testing KASAN for bug detection"
-	depends on m && KASAN
+	depends on m
 	help
 	  This is a test module doing various nasty things like
 	  out of bounds accesses, use after free. It is useful for testing
 	  kernel debugging features like KASAN.
+
+endif # KASAN