1 files changed, 496 insertions, 146 deletions

diff --git a/mm/kasan/report.c b/mm/kasan/report.c
index ca9418fe9232..62c01b4527eb 100644
--- a/mm/kasan/report.c
+++ b/mm/kasan/report.c
@@ -1,23 +1,21 @@
 // SPDX-License-Identifier: GPL-2.0
 /*
- * This file contains common generic and tag-based KASAN error reporting code.
+ * This file contains common KASAN error reporting code.
  *
  * Copyright (c) 2014 Samsung Electronics Co., Ltd.
  * Author: Andrey Ryabinin <ryabinin.a.a@gmail.com>
  *
  * Some code borrowed from https://github.com/xairy/kasan-prototype by
  *        Andrey Konovalov <andreyknvl@gmail.com>
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
- *
  */
 
+#include <kunit/test.h>
+#include <kunit/visibility.h>
 #include <linux/bitops.h>
 #include <linux/ftrace.h>
 #include <linux/init.h>
 #include <linux/kernel.h>
+#include <linux/lockdep.h>
 #include <linux/mm.h>
 #include <linux/printk.h>
 #include <linux/sched.h>
@@ -26,37 +24,50 @@
 #include <linux/stacktrace.h>
 #include <linux/string.h>
 #include <linux/types.h>
+#include <linux/vmalloc.h>
 #include <linux/kasan.h>
 #include <linux/module.h>
+#include <linux/sched/task_stack.h>
+#include <linux/uaccess.h>
+#include <trace/events/error_report.h>
 
 #include <asm/sections.h>
 
 #include "kasan.h"
 #include "../slab.h"
 
-/* Shadow layout customization. */
-#define SHADOW_BYTES_PER_BLOCK 1
-#define SHADOW_BLOCKS_PER_ROW 16
-#define SHADOW_BYTES_PER_ROW (SHADOW_BLOCKS_PER_ROW * SHADOW_BYTES_PER_BLOCK)
-#define SHADOW_ROWS_AROUND_ADDR 2
-
 static unsigned long kasan_flags;
 
 #define KASAN_BIT_REPORTED	0
 #define KASAN_BIT_MULTI_SHOT	1
 
-bool kasan_save_enable_multi_shot(void)
-{
-	return test_and_set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
-}
-EXPORT_SYMBOL_GPL(kasan_save_enable_multi_shot);
+enum kasan_arg_fault {
+	KASAN_ARG_FAULT_DEFAULT,
+	KASAN_ARG_FAULT_REPORT,
+	KASAN_ARG_FAULT_PANIC,
+	KASAN_ARG_FAULT_PANIC_ON_WRITE,
+};
 
-void kasan_restore_multi_shot(bool enabled)
+static enum kasan_arg_fault kasan_arg_fault __ro_after_init = KASAN_ARG_FAULT_DEFAULT;
+
+/* kasan.fault=report/panic */
+static int __init early_kasan_fault(char *arg)
 {
-	if (!enabled)
-		clear_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
+	if (!arg)
+		return -EINVAL;
+
+	if (!strcmp(arg, "report"))
+		kasan_arg_fault = KASAN_ARG_FAULT_REPORT;
+	else if (!strcmp(arg, "panic"))
+		kasan_arg_fault = KASAN_ARG_FAULT_PANIC;
+	else if (!strcmp(arg, "panic_on_write"))
+		kasan_arg_fault = KASAN_ARG_FAULT_PANIC_ON_WRITE;
+	else
+		return -EINVAL;
+
+	return 0;
 }
-EXPORT_SYMBOL_GPL(kasan_restore_multi_shot);
+early_param("kasan.fault", early_kasan_fault);
 
 static int __init kasan_set_multi_shot(char *str)
 {
@@ -65,108 +76,287 @@ static int __init kasan_set_multi_shot(char *str)
 }
 __setup("kasan_multi_shot", kasan_set_multi_shot);
 
-static void print_error_description(struct kasan_access_info *info)
+/*
+ * This function is used to check whether KASAN reports are suppressed for
+ * software KASAN modes via kasan_disable/enable_current() critical sections.
+ *
+ * This is done to avoid:
+ * 1. False-positive reports when accessing slab metadata,
+ * 2. Deadlocking when poisoned memory is accessed by the reporting code.
+ *
+ * Hardware Tag-Based KASAN instead relies on:
+ * For #1: Resetting tags via kasan_reset_tag().
+ * For #2: Suppression of tag checks via CPU, see report_suppress_start/end().
+ */
+static bool report_suppressed_sw(void)
 {
-	pr_err("BUG: KASAN: %s in %pS\n",
-		get_bug_type(info), (void *)info->ip);
-	pr_err("%s of size %zu at addr %px by task %s/%d\n",
-		info->is_write ? "Write" : "Read", info->access_size,
-		info->access_addr, current->comm, task_pid_nr(current));
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
+	if (current->kasan_depth)
+		return true;
+#endif
+	return false;
 }
 
-static DEFINE_SPINLOCK(report_lock);
-
-static void start_report(unsigned long *flags)
+static void report_suppress_start(void)
 {
+#ifdef CONFIG_KASAN_HW_TAGS
 	/*
-	 * Make sure we don't end up in loop.
+	 * Disable preemption for the duration of printing a KASAN report, as
+	 * hw_suppress_tag_checks_start() disables checks on the current CPU.
 	 */
+	preempt_disable();
+	hw_suppress_tag_checks_start();
+#else
 	kasan_disable_current();
-	spin_lock_irqsave(&report_lock, *flags);
+#endif
+}
+
+static void report_suppress_stop(void)
+{
+#ifdef CONFIG_KASAN_HW_TAGS
+	hw_suppress_tag_checks_stop();
+	preempt_enable();
+#else
+	kasan_enable_current();
+#endif
+}
+
+/*
+ * Used to avoid reporting more than one KASAN bug unless kasan_multi_shot
+ * is enabled. Note that KASAN tests effectively enable kasan_multi_shot
+ * for their duration.
+ */
+static bool report_enabled(void)
+{
+	if (test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
+		return true;
+	return !test_and_set_bit(KASAN_BIT_REPORTED, &kasan_flags);
+}
+
+#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST)
+
+VISIBLE_IF_KUNIT bool kasan_save_enable_multi_shot(void)
+{
+	return test_and_set_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
+}
+EXPORT_SYMBOL_IF_KUNIT(kasan_save_enable_multi_shot);
+
+VISIBLE_IF_KUNIT void kasan_restore_multi_shot(bool enabled)
+{
+	if (!enabled)
+		clear_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags);
+}
+EXPORT_SYMBOL_IF_KUNIT(kasan_restore_multi_shot);
+
+#endif
+
+#if IS_ENABLED(CONFIG_KASAN_KUNIT_TEST)
+
+/*
+ * Whether the KASAN KUnit test suite is currently being executed.
+ * Updated in kasan_test.c.
+ */
+static bool kasan_kunit_executing;
+
+VISIBLE_IF_KUNIT void kasan_kunit_test_suite_start(void)
+{
+	WRITE_ONCE(kasan_kunit_executing, true);
+}
+EXPORT_SYMBOL_IF_KUNIT(kasan_kunit_test_suite_start);
+
+VISIBLE_IF_KUNIT void kasan_kunit_test_suite_end(void)
+{
+	WRITE_ONCE(kasan_kunit_executing, false);
+}
+EXPORT_SYMBOL_IF_KUNIT(kasan_kunit_test_suite_end);
+
+static bool kasan_kunit_test_suite_executing(void)
+{
+	return READ_ONCE(kasan_kunit_executing);
+}
+
+#else /* CONFIG_KASAN_KUNIT_TEST */
+
+static inline bool kasan_kunit_test_suite_executing(void) { return false; }
+
+#endif /* CONFIG_KASAN_KUNIT_TEST */
+
+#if IS_ENABLED(CONFIG_KUNIT)
+
+static void fail_non_kasan_kunit_test(void)
+{
+	struct kunit *test;
+
+	if (kasan_kunit_test_suite_executing())
+		return;
+
+	test = current->kunit_test;
+	if (test)
+		kunit_set_failure(test);
+}
+
+#else /* CONFIG_KUNIT */
+
+static inline void fail_non_kasan_kunit_test(void) { }
+
+#endif /* CONFIG_KUNIT */
+
+static DEFINE_RAW_SPINLOCK(report_lock);
+
+static void start_report(unsigned long *flags, bool sync)
+{
+	fail_non_kasan_kunit_test();
+	/* Respect the /proc/sys/kernel/traceoff_on_warning interface. */
+	disable_trace_on_warning();
+	/* Do not allow LOCKDEP mangling KASAN reports. */
+	lockdep_off();
+	/* Make sure we don't end up in loop. */
+	report_suppress_start();
+	raw_spin_lock_irqsave(&report_lock, *flags);
 	pr_err("==================================================================\n");
 }
 
-static void end_report(unsigned long *flags)
+static void end_report(unsigned long *flags, const void *addr, bool is_write)
 {
+	if (addr)
+		trace_error_report_end(ERROR_DETECTOR_KASAN,
+				       (unsigned long)addr);
 	pr_err("==================================================================\n");
+	raw_spin_unlock_irqrestore(&report_lock, *flags);
+	if (!test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
+		check_panic_on_warn("KASAN");
+	switch (kasan_arg_fault) {
+	case KASAN_ARG_FAULT_DEFAULT:
+	case KASAN_ARG_FAULT_REPORT:
+		break;
+	case KASAN_ARG_FAULT_PANIC:
+		panic("kasan.fault=panic set ...\n");
+		break;
+	case KASAN_ARG_FAULT_PANIC_ON_WRITE:
+		if (is_write)
+			panic("kasan.fault=panic_on_write set ...\n");
+		break;
+	}
 	add_taint(TAINT_BAD_PAGE, LOCKDEP_NOW_UNRELIABLE);
-	spin_unlock_irqrestore(&report_lock, *flags);
-	if (panic_on_warn)
-		panic("panic_on_warn set ...\n");
-	kasan_enable_current();
+	lockdep_on();
+	report_suppress_stop();
+}
+
+static void print_error_description(struct kasan_report_info *info)
+{
+	pr_err("BUG: KASAN: %s in %pS\n", info->bug_type, (void *)info->ip);
+
+	if (info->type != KASAN_REPORT_ACCESS) {
+		pr_err("Free of addr %px by task %s/%d\n",
+			info->access_addr, current->comm, task_pid_nr(current));
+		return;
+	}
+
+	if (info->access_size)
+		pr_err("%s of size %zu at addr %px by task %s/%d\n",
+			info->is_write ? "Write" : "Read", info->access_size,
+			info->access_addr, current->comm, task_pid_nr(current));
+	else
+		pr_err("%s at addr %px by task %s/%d\n",
+			info->is_write ? "Write" : "Read",
+			info->access_addr, current->comm, task_pid_nr(current));
 }
 
 static void print_track(struct kasan_track *track, const char *prefix)
 {
-	pr_err("%s by task %u:\n", prefix, track->pid);
-	if (track->stack) {
-		struct stack_trace trace;
+#ifdef CONFIG_KASAN_EXTRA_INFO
+	u64 ts_nsec = track->timestamp;
+	unsigned long rem_usec;
 
-		depot_fetch_stack(track->stack, &trace);
-		print_stack_trace(&trace, 0);
-	} else {
+	ts_nsec <<= 9;
+	rem_usec = do_div(ts_nsec, NSEC_PER_SEC) / 1000;
+
+	pr_err("%s by task %u on cpu %d at %lu.%06lus:\n",
+			prefix, track->pid, track->cpu,
+			(unsigned long)ts_nsec, rem_usec);
+#else
+	pr_err("%s by task %u:\n", prefix, track->pid);
+#endif /* CONFIG_KASAN_EXTRA_INFO */
+	if (track->stack)
+		stack_depot_print(track->stack);
+	else
 		pr_err("(stack is not available)\n");
-	}
 }
 
-static struct page *addr_to_page(const void *addr)
+static inline struct page *addr_to_page(const void *addr)
 {
-	if ((addr >= (void *)PAGE_OFFSET) &&
-			(addr < high_memory))
+	if (virt_addr_valid(addr))
 		return virt_to_head_page(addr);
 	return NULL;
 }
 
-static void describe_object_addr(struct kmem_cache *cache, void *object,
-				const void *addr)
+static void describe_object_addr(const void *addr, struct kasan_report_info *info)
 {
 	unsigned long access_addr = (unsigned long)addr;
-	unsigned long object_addr = (unsigned long)object;
-	const char *rel_type;
+	unsigned long object_addr = (unsigned long)info->object;
+	const char *rel_type, *region_state = "";
 	int rel_bytes;
 
 	pr_err("The buggy address belongs to the object at %px\n"
 	       " which belongs to the cache %s of size %d\n",
-		object, cache->name, cache->object_size);
-
-	if (!addr)
-		return;
+		info->object, info->cache->name, info->cache->object_size);
 
 	if (access_addr < object_addr) {
 		rel_type = "to the left";
 		rel_bytes = object_addr - access_addr;
-	} else if (access_addr >= object_addr + cache->object_size) {
+	} else if (access_addr >= object_addr + info->alloc_size) {
 		rel_type = "to the right";
-		rel_bytes = access_addr - (object_addr + cache->object_size);
+		rel_bytes = access_addr - (object_addr + info->alloc_size);
 	} else {
 		rel_type = "inside";
 		rel_bytes = access_addr - object_addr;
 	}
 
+	/*
+	 * Tag-Based modes use the stack ring to infer the bug type, but the
+	 * memory region state description is generated based on the metadata.
+	 * Thus, defining the region state as below can contradict the metadata.
+	 * Fixing this requires further improvements, so only infer the state
+	 * for the Generic mode.
+	 */
+	if (IS_ENABLED(CONFIG_KASAN_GENERIC)) {
+		if (strcmp(info->bug_type, "slab-out-of-bounds") == 0)
+			region_state = "allocated ";
+		else if (strcmp(info->bug_type, "slab-use-after-free") == 0)
+			region_state = "freed ";
+	}
+
 	pr_err("The buggy address is located %d bytes %s of\n"
-	       " %d-byte region [%px, %px)\n",
-		rel_bytes, rel_type, cache->object_size, (void *)object_addr,
-		(void *)(object_addr + cache->object_size));
+	       " %s%zu-byte region [%px, %px)\n",
+	       rel_bytes, rel_type, region_state, info->alloc_size,
+	       (void *)object_addr, (void *)(object_addr + info->alloc_size));
 }
 
-static void describe_object(struct kmem_cache *cache, void *object,
-				const void *addr)
+static void describe_object_stacks(struct kasan_report_info *info)
 {
-	struct kasan_alloc_meta *alloc_info = get_alloc_info(cache, object);
-
-	if (cache->flags & SLAB_KASAN) {
-		print_track(&alloc_info->alloc_track, "Allocated");
+	if (info->alloc_track.stack) {
+		print_track(&info->alloc_track, "Allocated");
 		pr_err("\n");
-		print_track(&alloc_info->free_track, "Freed");
+	}
+
+	if (info->free_track.stack) {
+		print_track(&info->free_track, "Freed");
 		pr_err("\n");
 	}
 
-	describe_object_addr(cache, object, addr);
+	kasan_print_aux_stacks(info->cache, info->object);
+}
+
+static void describe_object(const void *addr, struct kasan_report_info *info)
+{
+	if (kasan_stack_collection_enabled())
+		describe_object_stacks(info);
+	describe_object_addr(addr, info);
 }
 
 static inline bool kernel_or_module_addr(const void *addr)
 {
-	if (addr >= (void *)_stext && addr < (void *)_end)
+	if (is_kernel((unsigned long)addr))
 		return true;
 	if (is_module_address((unsigned long)addr))
 		return true;
@@ -180,146 +370,306 @@ static inline bool init_task_stack_addr(const void *addr)
 			sizeof(init_thread_union.stack));
 }
 
-static void print_address_description(void *addr)
+static void print_address_description(void *addr, u8 tag,
+				      struct kasan_report_info *info)
 {
 	struct page *page = addr_to_page(addr);
 
-	dump_stack();
+	dump_stack_lvl(KERN_ERR);
 	pr_err("\n");
 
-	if (page && PageSlab(page)) {
-		struct kmem_cache *cache = page->slab_cache;
-		void *object = nearest_obj(cache, page,	addr);
-
-		describe_object(cache, object, addr);
+	if (info->cache && info->object) {
+		describe_object(addr, info);
+		pr_err("\n");
 	}
 
 	if (kernel_or_module_addr(addr) && !init_task_stack_addr(addr)) {
 		pr_err("The buggy address belongs to the variable:\n");
 		pr_err(" %pS\n", addr);
+		pr_err("\n");
+	}
+
+	if (object_is_on_stack(addr)) {
+		/*
+		 * Currently, KASAN supports printing frame information only
+		 * for accesses to the task's own stack.
+		 */
+		kasan_print_address_stack_frame(addr);
+		pr_err("\n");
+	}
+
+	if (is_vmalloc_addr(addr)) {
+		pr_err("The buggy address belongs to a");
+		if (!vmalloc_dump_obj(addr))
+			pr_cont(" vmalloc virtual mapping\n");
+		page = vmalloc_to_page(addr);
 	}
 
 	if (page) {
-		pr_err("The buggy address belongs to the page:\n");
+		pr_err("The buggy address belongs to the physical page:\n");
 		dump_page(page, "kasan: bad access detected");
+		pr_err("\n");
 	}
 }
 
-static bool row_is_guilty(const void *row, const void *guilty)
+static bool meta_row_is_guilty(const void *row, const void *addr)
 {
-	return (row <= guilty) && (guilty < row + SHADOW_BYTES_PER_ROW);
+	return (row <= addr) && (addr < row + META_MEM_BYTES_PER_ROW);
 }
 
-static int shadow_pointer_offset(const void *row, const void *shadow)
+static int meta_pointer_offset(const void *row, const void *addr)
 {
-	/* The length of ">ff00ff00ff00ff00: " is
-	 *    3 + (BITS_PER_LONG/8)*2 chars.
+	/*
+	 * Memory state around the buggy address:
+	 *  ff00ff00ff00ff00: 00 00 00 05 fe fe fe fe fe fe fe fe fe fe fe fe
+	 *  ...
+	 *
+	 * The length of ">ff00ff00ff00ff00: " is
+	 *    3 + (BITS_PER_LONG / 8) * 2 chars.
+	 * The length of each granule metadata is 2 bytes
+	 *    plus 1 byte for space.
 	 */
-	return 3 + (BITS_PER_LONG/8)*2 + (shadow - row)*2 +
-		(shadow - row) / SHADOW_BYTES_PER_BLOCK + 1;
+	return 3 + (BITS_PER_LONG / 8) * 2 +
+		(addr - row) / KASAN_GRANULE_SIZE * 3 + 1;
 }
 
-static void print_shadow_for_address(const void *addr)
+static void print_memory_metadata(const void *addr)
 {
 	int i;
-	const void *shadow = kasan_mem_to_shadow(addr);
-	const void *shadow_row;
+	void *row;
 
-	shadow_row = (void *)round_down((unsigned long)shadow,
-					SHADOW_BYTES_PER_ROW)
-		- SHADOW_ROWS_AROUND_ADDR * SHADOW_BYTES_PER_ROW;
+	row = (void *)round_down((unsigned long)addr, META_MEM_BYTES_PER_ROW)
+			- META_ROWS_AROUND_ADDR * META_MEM_BYTES_PER_ROW;
 
 	pr_err("Memory state around the buggy address:\n");
 
-	for (i = -SHADOW_ROWS_AROUND_ADDR; i <= SHADOW_ROWS_AROUND_ADDR; i++) {
-		const void *kaddr = kasan_shadow_to_mem(shadow_row);
-		char buffer[4 + (BITS_PER_LONG/8)*2];
-		char shadow_buf[SHADOW_BYTES_PER_ROW];
+	for (i = -META_ROWS_AROUND_ADDR; i <= META_ROWS_AROUND_ADDR; i++) {
+		char buffer[4 + (BITS_PER_LONG / 8) * 2];
+		char metadata[META_BYTES_PER_ROW];
 
 		snprintf(buffer, sizeof(buffer),
-			(i == 0) ? ">%px: " : " %px: ", kaddr);
+				(i == 0) ? ">%px: " : " %px: ", row);
+
 		/*
 		 * We should not pass a shadow pointer to generic
 		 * function, because generic functions may try to
 		 * access kasan mapping for the passed address.
 		 */
-		memcpy(shadow_buf, shadow_row, SHADOW_BYTES_PER_ROW);
+		kasan_metadata_fetch_row(&metadata[0], row);
+
 		print_hex_dump(KERN_ERR, buffer,
-			DUMP_PREFIX_NONE, SHADOW_BYTES_PER_ROW, 1,
-			shadow_buf, SHADOW_BYTES_PER_ROW, 0);
+			DUMP_PREFIX_NONE, META_BYTES_PER_ROW, 1,
+			metadata, META_BYTES_PER_ROW, 0);
 
-		if (row_is_guilty(shadow_row, shadow))
-			pr_err("%*c\n",
-				shadow_pointer_offset(shadow_row, shadow),
-				'^');
+		if (meta_row_is_guilty(row, addr))
+			pr_err("%*c\n", meta_pointer_offset(row, addr), '^');
 
-		shadow_row += SHADOW_BYTES_PER_ROW;
+		row += META_MEM_BYTES_PER_ROW;
 	}
 }
 
-static bool report_enabled(void)
+static void print_report(struct kasan_report_info *info)
 {
-	if (current->kasan_depth)
-		return false;
-	if (test_bit(KASAN_BIT_MULTI_SHOT, &kasan_flags))
-		return true;
-	return !test_and_set_bit(KASAN_BIT_REPORTED, &kasan_flags);
+	void *addr = kasan_reset_tag((void *)info->access_addr);
+	u8 tag = get_tag((void *)info->access_addr);
+
+	print_error_description(info);
+	if (addr_has_metadata(addr))
+		kasan_print_tags(tag, info->first_bad_addr);
+	pr_err("\n");
+
+	if (addr_has_metadata(addr)) {
+		print_address_description(addr, tag, info);
+		print_memory_metadata(info->first_bad_addr);
+	} else {
+		dump_stack_lvl(KERN_ERR);
+	}
 }
 
-void kasan_report_invalid_free(void *object, unsigned long ip)
+static void complete_report_info(struct kasan_report_info *info)
 {
-	unsigned long flags;
+	void *addr = kasan_reset_tag((void *)info->access_addr);
+	struct slab *slab;
 
-	start_report(&flags);
-	pr_err("BUG: KASAN: double-free or invalid-free in %pS\n", (void *)ip);
-	print_tags(get_tag(object), reset_tag(object));
-	object = reset_tag(object);
-	pr_err("\n");
-	print_address_description(object);
-	pr_err("\n");
-	print_shadow_for_address(object);
-	end_report(&flags);
+	if (info->type == KASAN_REPORT_ACCESS)
+		info->first_bad_addr = kasan_find_first_bad_addr(
+					(void *)info->access_addr, info->access_size);
+	else
+		info->first_bad_addr = addr;
+
+	slab = kasan_addr_to_slab(addr);
+	if (slab) {
+		info->cache = slab->slab_cache;
+		info->object = nearest_obj(info->cache, slab, addr);
+
+		/* Try to determine allocation size based on the metadata. */
+		info->alloc_size = kasan_get_alloc_size(info->object, info->cache);
+		/* Fallback to the object size if failed. */
+		if (!info->alloc_size)
+			info->alloc_size = info->cache->object_size;
+	} else
+		info->cache = info->object = NULL;
+
+	switch (info->type) {
+	case KASAN_REPORT_INVALID_FREE:
+		info->bug_type = "invalid-free";
+		break;
+	case KASAN_REPORT_DOUBLE_FREE:
+		info->bug_type = "double-free";
+		break;
+	default:
+		/* bug_type filled in by kasan_complete_mode_report_info. */
+		break;
+	}
+
+	/* Fill in mode-specific report info fields. */
+	kasan_complete_mode_report_info(info);
 }
 
-void kasan_report(unsigned long addr, size_t size,
-		bool is_write, unsigned long ip)
+void kasan_report_invalid_free(void *ptr, unsigned long ip, enum kasan_report_type type)
 {
-	struct kasan_access_info info;
-	void *tagged_addr;
-	void *untagged_addr;
 	unsigned long flags;
+	struct kasan_report_info info;
 
-	if (likely(!report_enabled()))
+	/*
+	 * Do not check report_suppressed_sw(), as an invalid-free cannot be
+	 * caused by accessing poisoned memory and thus should not be suppressed
+	 * by kasan_disable/enable_current() critical sections.
+	 *
+	 * Note that for Hardware Tag-Based KASAN, kasan_report_invalid_free()
+	 * is triggered by explicit tag checks and not by the ones performed by
+	 * the CPU. Thus, reporting invalid-free is not suppressed as well.
+	 */
+	if (unlikely(!report_enabled()))
 		return;
 
-	disable_trace_on_warning();
+	start_report(&flags, true);
 
-	tagged_addr = (void *)addr;
-	untagged_addr = reset_tag(tagged_addr);
+	__memset(&info, 0, sizeof(info));
+	info.type = type;
+	info.access_addr = ptr;
+	info.access_size = 0;
+	info.is_write = false;
+	info.ip = ip;
 
-	info.access_addr = tagged_addr;
-	if (addr_has_shadow(untagged_addr))
-		info.first_bad_addr = find_first_bad_addr(tagged_addr, size);
-	else
-		info.first_bad_addr = untagged_addr;
+	complete_report_info(&info);
+
+	print_report(&info);
+
+	/*
+	 * Invalid free is considered a "write" since the allocator's metadata
+	 * updates involves writes.
+	 */
+	end_report(&flags, ptr, true);
+}
+
+/*
+ * kasan_report() is the only reporting function that uses
+ * user_access_save/restore(): kasan_report_invalid_free() cannot be called
+ * from a UACCESS region, and kasan_report_async() is not used on x86.
+ */
+bool kasan_report(const void *addr, size_t size, bool is_write,
+			unsigned long ip)
+{
+	bool ret = true;
+	unsigned long ua_flags = user_access_save();
+	unsigned long irq_flags;
+	struct kasan_report_info info;
+
+	if (unlikely(report_suppressed_sw()) || unlikely(!report_enabled())) {
+		ret = false;
+		goto out;
+	}
+
+	start_report(&irq_flags, true);
+
+	__memset(&info, 0, sizeof(info));
+	info.type = KASAN_REPORT_ACCESS;
+	info.access_addr = addr;
 	info.access_size = size;
 	info.is_write = is_write;
 	info.ip = ip;
 
-	start_report(&flags);
+	complete_report_info(&info);
+
+	print_report(&info);
+
+	end_report(&irq_flags, (void *)addr, is_write);
+
+out:
+	user_access_restore(ua_flags);
+
+	return ret;
+}
+
+#ifdef CONFIG_KASAN_HW_TAGS
+void kasan_report_async(void)
+{
+	unsigned long flags;
+
+	/*
+	 * Do not check report_suppressed_sw(), as
+	 * kasan_disable/enable_current() critical sections do not affect
+	 * Hardware Tag-Based KASAN.
+	 */
+	if (unlikely(!report_enabled()))
+		return;
 
-	print_error_description(&info);
-	if (addr_has_shadow(untagged_addr))
-		print_tags(get_tag(tagged_addr), info.first_bad_addr);
+	start_report(&flags, false);
+	pr_err("BUG: KASAN: invalid-access\n");
+	pr_err("Asynchronous fault: no details available\n");
 	pr_err("\n");
+	dump_stack_lvl(KERN_ERR);
+	/*
+	 * Conservatively set is_write=true, because no details are available.
+	 * In this mode, kasan.fault=panic_on_write is like kasan.fault=panic.
+	 */
+	end_report(&flags, NULL, true);
+}
+#endif /* CONFIG_KASAN_HW_TAGS */
 
-	if (addr_has_shadow(untagged_addr)) {
-		print_address_description(untagged_addr);
-		pr_err("\n");
-		print_shadow_for_address(info.first_bad_addr);
-	} else {
-		dump_stack();
-	}
+#if defined(CONFIG_KASAN_GENERIC) || defined(CONFIG_KASAN_SW_TAGS)
+/*
+ * With compiler-based KASAN modes, accesses to bogus pointers (outside of the
+ * mapped kernel address space regions) cause faults when KASAN tries to check
+ * the shadow memory before the actual memory access. This results in cryptic
+ * GPF reports, which are hard for users to interpret. This hook helps users to
+ * figure out what the original bogus pointer was.
+ */
+void kasan_non_canonical_hook(unsigned long addr)
+{
+	unsigned long orig_addr;
+	const char *bug_type;
 
-	end_report(&flags);
+	/*
+	 * All addresses that came as a result of the memory-to-shadow mapping
+	 * (even for bogus pointers) must be >= KASAN_SHADOW_OFFSET.
+	 */
+	if (addr < KASAN_SHADOW_OFFSET)
+		return;
+
+	orig_addr = (unsigned long)kasan_shadow_to_mem((void *)addr);
+
+	/*
+	 * For faults near the shadow address for NULL, we can be fairly certain
+	 * that this is a KASAN shadow memory access.
+	 * For faults that correspond to the shadow for low or high canonical
+	 * addresses, we can still be pretty sure: these shadow regions are a
+	 * fairly narrow chunk of the address space.
+	 * But the shadow for non-canonical addresses is a really large chunk
+	 * of the address space. For this case, we still print the decoded
+	 * address, but make it clear that this is not necessarily what's
+	 * actually going on.
+	 */
+	if (orig_addr < PAGE_SIZE)
+		bug_type = "null-ptr-deref";
+	else if (orig_addr < TASK_SIZE)
+		bug_type = "probably user-memory-access";
+	else if (addr_in_shadow((void *)addr))
+		bug_type = "probably wild-memory-access";
+	else
+		bug_type = "maybe wild-memory-access";
+	pr_alert("KASAN: %s in range [0x%016lx-0x%016lx]\n", bug_type,
+		 orig_addr, orig_addr + KASAN_GRANULE_SIZE - 1);
 }
+#endif