Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "18 patches.

  Subsystems affected by this patch series: mm (pagealloc, memcg, kasan,
  memory-failure, and highmem), ubsan, proc, and MAINTAINERS"

* emailed patches from Andrew Morton <[email protected]>:
  MAINTAINERS: add a couple more files to the Clang/LLVM section
  proc_sysctl: fix oops caused by incorrect command parameters
  powerpc/mm/highmem: use __set_pte_at() for kmap_local()
  mips/mm/highmem: use set_pte() for kmap_local()
  mm/highmem: prepare for overriding set_pte_at()
  sparc/mm/highmem: flush cache and TLB
  mm: fix page reference leak in soft_offline_page()
  ubsan: disable unsigned-overflow check for i386
  kasan, mm: fix resetting page_alloc tags for HW_TAGS
  kasan, mm: fix conflicts with init_on_alloc/free
  kasan: fix HW_TAGS boot parameters
  kasan: fix incorrect arguments passing in kasan_add_zero_shadow
  kasan: fix unaligned address is unhandled in kasan_remove_zero_shadow
  mm: fix numa stats for thp migration
  mm: memcg: fix memcg file_dirty numa stat
  mm: memcg/slab: optimize objcg stock draining
  mm: fix initialization of struct page for holes in memory layout
  x86/setup: don't remove E820_TYPE_RAM for pfn 0

Author: torvalds

Documentation/dev-tools/kasan.rst

@@ -160,29 +160,14 @@ intended for use in production as a security mitigation. Therefore it supports
 boot parameters that allow to disable KASAN competely or otherwise control
 particular KASAN features.
 
-The things that can be controlled are:
+- ``kasan=off`` or ``=on`` controls whether KASAN is enabled (default: ``on``).
 
-1. Whether KASAN is enabled at all.
-2. Whether KASAN collects and saves alloc/free stacks.
-3. Whether KASAN panics on a detected bug or not.
+- ``kasan.stacktrace=off`` or ``=on`` disables or enables alloc and free stack
+  traces collection (default: ``on`` for ``CONFIG_DEBUG_KERNEL=y``, otherwise
+  ``off``).
 
-The ``kasan.mode`` boot parameter allows to choose one of three main modes:
-
-- ``kasan.mode=off`` - KASAN is disabled, no tag checks are performed
-- ``kasan.mode=prod`` - only essential production features are enabled
-- ``kasan.mode=full`` - all KASAN features are enabled
-
-The chosen mode provides default control values for the features mentioned
-above. However it's also possible to override the default values by providing:
-
-- ``kasan.stacktrace=off`` or ``=on`` - enable alloc/free stack collection
-					(default: ``on`` for ``mode=full``,
-					 otherwise ``off``)
-- ``kasan.fault=report`` or ``=panic`` - only print KASAN report or also panic
-					 (default: ``report``)
-
-If ``kasan.mode`` parameter is not provided, it defaults to ``full`` when
-``CONFIG_DEBUG_KERNEL`` is enabled, and to ``prod`` otherwise.
+- ``kasan.fault=report`` or ``=panic`` controls whether to only print a KASAN
+  report or also panic the kernel (default: ``report``).
 
 For developers
 ~~~~~~~~~~~~~~

MAINTAINERS

@@ -4311,7 +4311,9 @@ W:	https://clangbuiltlinux.github.io/
 B:	https://github.com/ClangBuiltLinux/linux/issues
 C:	irc://chat.freenode.net/clangbuiltlinux
 F:	Documentation/kbuild/llvm.rst
+F:	include/linux/compiler-clang.h
 F:	scripts/clang-tools/
+F:	scripts/clang-version.sh
 F:	scripts/lld-version.sh
 K:	\b(?i:clang|llvm)\b
 

arch/mips/include/asm/highmem.h

@@ -51,6 +51,7 @@ extern void kmap_flush_tlb(unsigned long addr);
 
 #define flush_cache_kmaps()	BUG_ON(cpu_has_dc_aliases)
 
+#define arch_kmap_local_set_pte(mm, vaddr, ptep, ptev)	set_pte(ptep, ptev)
 #define arch_kmap_local_post_map(vaddr, pteval)	local_flush_tlb_one(vaddr)
 #define arch_kmap_local_post_unmap(vaddr)	local_flush_tlb_one(vaddr)
 

arch/powerpc/include/asm/highmem.h

@@ -58,6 +58,8 @@ extern pte_t *pkmap_page_table;
 
 #define flush_cache_kmaps()	flush_cache_all()
 
+#define arch_kmap_local_set_pte(mm, vaddr, ptep, ptev)	\
+	__set_pte_at(mm, vaddr, ptep, ptev, 1)
 #define arch_kmap_local_post_map(vaddr, pteval)	\
 	local_flush_tlb_page(NULL, vaddr)
 #define arch_kmap_local_post_unmap(vaddr)	\

arch/sparc/include/asm/highmem.h

@@ -50,10 +50,11 @@ extern pte_t *pkmap_page_table;
 
 #define flush_cache_kmaps()	flush_cache_all()
 
-/* FIXME: Use __flush_tlb_one(vaddr) instead of flush_cache_all() -- Anton */
-#define arch_kmap_local_post_map(vaddr, pteval)	flush_cache_all()
-#define arch_kmap_local_post_unmap(vaddr)	flush_cache_all()
-
+/* FIXME: Use __flush_*_one(vaddr) instead of flush_*_all() -- Anton */
+#define arch_kmap_local_pre_map(vaddr, pteval)	flush_cache_all()
+#define arch_kmap_local_pre_unmap(vaddr)	flush_cache_all()
+#define arch_kmap_local_post_map(vaddr, pteval)	flush_tlb_all()
+#define arch_kmap_local_post_unmap(vaddr)	flush_tlb_all()
 
 #endif /* __KERNEL__ */
 

arch/x86/kernel/setup.c

@@ -660,17 +660,6 @@ static void __init trim_platform_memory_ranges(void)
 
 static void __init trim_bios_range(void)
 {
-	/*
-	 * A special case is the first 4Kb of memory;
-	 * This is a BIOS owned area, not kernel ram, but generally
-	 * not listed as such in the E820 table.
-	 *
-	 * This typically reserves additional memory (64KiB by default)
-	 * since some BIOSes are known to corrupt low memory.  See the
-	 * Kconfig help text for X86_RESERVE_LOW.
-	 */
-	e820__range_update(0, PAGE_SIZE, E820_TYPE_RAM, E820_TYPE_RESERVED);
-
 	/*
 	 * special case: Some BIOSes report the PC BIOS
 	 * area (640Kb -> 1Mb) as RAM even though it is not.
@@ -728,6 +717,15 @@ early_param("reservelow", parse_reservelow);
 
 static void __init trim_low_memory_range(void)
 {
+	/*
+	 * A special case is the first 4Kb of memory;
+	 * This is a BIOS owned area, not kernel ram, but generally
+	 * not listed as such in the E820 table.
+	 *
+	 * This typically reserves additional memory (64KiB by default)
+	 * since some BIOSes are known to corrupt low memory.  See the
+	 * Kconfig help text for X86_RESERVE_LOW.
+	 */
 	memblock_reserve(0, ALIGN(reserve_low, PAGE_SIZE));
 }
 

fs/proc/proc_sysctl.c

@@ -1770,6 +1770,12 @@ static int process_sysctl_arg(char *param, char *val,
 			return 0;
 	}
 
+	if (!val)
+		return -EINVAL;
+	len = strlen(val);
+	if (len == 0)
+		return -EINVAL;
+
 	/*
 	 * To set sysctl options, we use a temporary mount of proc, look up the
 	 * respective sys/ file and write to it. To avoid mounting it when no
@@ -1811,7 +1817,6 @@ static int process_sysctl_arg(char *param, char *val,
 				file, param, val);
 		goto out;
 	}
-	len = strlen(val);
 	wret = kernel_write(file, val, len, &pos);
 	if (wret < 0) {
 		err = wret;

lib/Kconfig.ubsan

@@ -123,6 +123,7 @@ config UBSAN_SIGNED_OVERFLOW
 config UBSAN_UNSIGNED_OVERFLOW
 	bool "Perform checking for unsigned arithmetic overflow"
 	depends on $(cc-option,-fsanitize=unsigned-integer-overflow)
+	depends on !X86_32 # avoid excessive stack usage on x86-32/clang
 	help
 	  This option enables -fsanitize=unsigned-integer-overflow which checks
 	  for overflow of any arithmetic operations with unsigned integers. This

mm/highmem.c

@@ -473,6 +473,11 @@ static inline void *arch_kmap_local_high_get(struct page *page)
 }
 #endif
 
+#ifndef arch_kmap_local_set_pte
+#define arch_kmap_local_set_pte(mm, vaddr, ptep, ptev)	\
+	set_pte_at(mm, vaddr, ptep, ptev)
+#endif
+
 /* Unmap a local mapping which was obtained by kmap_high_get() */
 static inline bool kmap_high_unmap_local(unsigned long vaddr)
 {
@@ -515,7 +520,7 @@ void *__kmap_local_pfn_prot(unsigned long pfn, pgprot_t prot)
 	vaddr = __fix_to_virt(FIX_KMAP_BEGIN + idx);
 	BUG_ON(!pte_none(*(kmap_pte - idx)));
 	pteval = pfn_pte(pfn, prot);
-	set_pte_at(&init_mm, vaddr, kmap_pte - idx, pteval);
+	arch_kmap_local_set_pte(&init_mm, vaddr, kmap_pte - idx, pteval);
 	arch_kmap_local_post_map(vaddr, pteval);
 	current->kmap_ctrl.pteval[kmap_local_idx()] = pteval;
 	preempt_enable();

mm/kasan/hw_tags.c

@@ -19,11 +19,10 @@
 
 #include "kasan.h"
 
-enum kasan_arg_mode {
-	KASAN_ARG_MODE_DEFAULT,
-	KASAN_ARG_MODE_OFF,
-	KASAN_ARG_MODE_PROD,
-	KASAN_ARG_MODE_FULL,
+enum kasan_arg {
+	KASAN_ARG_DEFAULT,
+	KASAN_ARG_OFF,
+	KASAN_ARG_ON,
 };
 
 enum kasan_arg_stacktrace {
@@ -38,7 +37,7 @@ enum kasan_arg_fault {
 	KASAN_ARG_FAULT_PANIC,
 };
 
-static enum kasan_arg_mode kasan_arg_mode __ro_after_init;
+static enum kasan_arg kasan_arg __ro_after_init;
 static enum kasan_arg_stacktrace kasan_arg_stacktrace __ro_after_init;
 static enum kasan_arg_fault kasan_arg_fault __ro_after_init;
 
@@ -52,26 +51,24 @@ DEFINE_STATIC_KEY_FALSE(kasan_flag_stacktrace);
 /* Whether panic or disable tag checking on fault. */
 bool kasan_flag_panic __ro_after_init;
 
-/* kasan.mode=off/prod/full */
-static int __init early_kasan_mode(char *arg)
+/* kasan=off/on */
+static int __init early_kasan_flag(char *arg)
 {
 	if (!arg)
 		return -EINVAL;
 
 	if (!strcmp(arg, "off"))
-		kasan_arg_mode = KASAN_ARG_MODE_OFF;
-	else if (!strcmp(arg, "prod"))
-		kasan_arg_mode = KASAN_ARG_MODE_PROD;
-	else if (!strcmp(arg, "full"))
-		kasan_arg_mode = KASAN_ARG_MODE_FULL;
+		kasan_arg = KASAN_ARG_OFF;
+	else if (!strcmp(arg, "on"))
+		kasan_arg = KASAN_ARG_ON;
 	else
 		return -EINVAL;
 
 	return 0;
 }
-early_param("kasan.mode", early_kasan_mode);
+early_param("kasan", early_kasan_flag);
 
-/* kasan.stack=off/on */
+/* kasan.stacktrace=off/on */
 static int __init early_kasan_flag_stacktrace(char *arg)
 {
 	if (!arg)
@@ -113,8 +110,8 @@ void kasan_init_hw_tags_cpu(void)
 	 * as this function is only called for MTE-capable hardware.
 	 */
 
-	/* If KASAN is disabled, do nothing. */
-	if (kasan_arg_mode == KASAN_ARG_MODE_OFF)
+	/* If KASAN is disabled via command line, don't initialize it. */
+	if (kasan_arg == KASAN_ARG_OFF)
 		return;
 
 	hw_init_tags(KASAN_TAG_MAX);
@@ -124,43 +121,28 @@ void kasan_init_hw_tags_cpu(void)
 /* kasan_init_hw_tags() is called once on boot CPU. */
 void __init kasan_init_hw_tags(void)
 {
-	/* If hardware doesn't support MTE, do nothing. */
+	/* If hardware doesn't support MTE, don't initialize KASAN. */
 	if (!system_supports_mte())
 		return;
 
-	/* Choose KASAN mode if kasan boot parameter is not provided. */
-	if (kasan_arg_mode == KASAN_ARG_MODE_DEFAULT) {
-		if (IS_ENABLED(CONFIG_DEBUG_KERNEL))
-			kasan_arg_mode = KASAN_ARG_MODE_FULL;
-		else
-			kasan_arg_mode = KASAN_ARG_MODE_PROD;
-	}
-
-	/* Preset parameter values based on the mode. */
-	switch (kasan_arg_mode) {
-	case KASAN_ARG_MODE_DEFAULT:
-		/* Shouldn't happen as per the check above. */
-		WARN_ON(1);
-		return;
-	case KASAN_ARG_MODE_OFF:
-		/* If KASAN is disabled, do nothing. */
+	/* If KASAN is disabled via command line, don't initialize it. */
+	if (kasan_arg == KASAN_ARG_OFF)
 		return;
-	case KASAN_ARG_MODE_PROD:
-		static_branch_enable(&kasan_flag_enabled);
-		break;
-	case KASAN_ARG_MODE_FULL:
-		static_branch_enable(&kasan_flag_enabled);
-		static_branch_enable(&kasan_flag_stacktrace);
-		break;
-	}
 
-	/* Now, optionally override the presets. */
+	/* Enable KASAN. */
+	static_branch_enable(&kasan_flag_enabled);
 
 	switch (kasan_arg_stacktrace) {
 	case KASAN_ARG_STACKTRACE_DEFAULT:
+		/*
+		 * Default to enabling stack trace collection for
+		 * debug kernels.
+		 */
+		if (IS_ENABLED(CONFIG_DEBUG_KERNEL))
+			static_branch_enable(&kasan_flag_stacktrace);
 		break;
 	case KASAN_ARG_STACKTRACE_OFF:
-		static_branch_disable(&kasan_flag_stacktrace);
+		/* Do nothing, kasan_flag_stacktrace keeps its default value. */
 		break;
 	case KASAN_ARG_STACKTRACE_ON:
 		static_branch_enable(&kasan_flag_stacktrace);
@@ -169,11 +151,16 @@ void __init kasan_init_hw_tags(void)
 
 	switch (kasan_arg_fault) {
 	case KASAN_ARG_FAULT_DEFAULT:
+		/*
+		 * Default to no panic on report.
+		 * Do nothing, kasan_flag_panic keeps its default value.
+		 */
 		break;
 	case KASAN_ARG_FAULT_REPORT:
-		kasan_flag_panic = false;
+		/* Do nothing, kasan_flag_panic keeps its default value. */
 		break;
 	case KASAN_ARG_FAULT_PANIC:
+		/* Enable panic on report. */
 		kasan_flag_panic = true;
 		break;
 	}