Merge tag 'mm-hotfixes-stable-2022-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc hotfixes from Andrew Morton:
 "Eight fix pre-6.0 bugs and the remainder address issues which were
  introduced in the 6.1-rc merge cycle, or address issues which aren't
  considered sufficiently serious to warrant a -stable backport"

* tag 'mm-hotfixes-stable-2022-10-28' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (23 commits)
  mm: multi-gen LRU: move lru_gen_add_mm() out of IRQ-off region
  lib: maple_tree: remove unneeded initialization in mtree_range_walk()
  mmap: fix remap_file_pages() regression
  mm/shmem: ensure proper fallback if page faults
  mm/userfaultfd: replace kmap/kmap_atomic() with kmap_local_page()
  x86: fortify: kmsan: fix KMSAN fortify builds
  x86: asm: make sure __put_user_size() evaluates pointer once
  Kconfig.debug: disable CONFIG_FRAME_WARN for KMSAN by default
  x86/purgatory: disable KMSAN instrumentation
  mm: kmsan: export kmsan_copy_page_meta()
  mm: migrate: fix return value if all subpages of THPs are migrated successfully
  mm/uffd: fix vma check on userfault for wp
  mm: prep_compound_tail() clear page->private
  mm,madvise,hugetlb: fix unexpected data loss with MADV_DONTNEED on hugetlbfs
  mm/page_isolation: fix clang deadcode warning
  fs/ext4/super.c: remove unused `deprecated_msg'
  ipc/msg.c: fix percpu_counter use after free
  memory tier, sysfs: rename attribute "nodes" to "nodelist"
  MAINTAINERS: git://github.com -> https://github.com for nilfs2
  mm/kmemleak: prevent soft lockup in kmemleak_scan()'s object iteration loops
  ...

Documentation/ABI/testing/sysfs-kernel-mm-memory-tiers

@@ -10,7 +10,7 @@ Description:	A collection of all the memory tiers allocated.
 
 
 What:		/sys/devices/virtual/memory_tiering/memory_tierN/
-		/sys/devices/virtual/memory_tiering/memory_tierN/nodes
+		/sys/devices/virtual/memory_tiering/memory_tierN/nodelist
 Date:		August 2022
 Contact:	Linux memory management mailing list <linux-mm@kvack.org>
 Description:	Directory with details of a specific memory tier
@@ -21,5 +21,5 @@ Description:	Directory with details of a specific memory tier
 		A smaller value of N implies a higher (faster) memory tier in the
 		hierarchy.
 
-		nodes: NUMA nodes that are part of this memory tier.
+		nodelist: NUMA nodes that are part of this memory tier.
 

MAINTAINERS

@@ -14523,7 +14523,7 @@ L:	linux-nilfs@vger.kernel.org
 S:	Supported
 W:	https://nilfs.sourceforge.io/
 W:	https://nilfs.osdn.jp/
-T:	git git://github.com/konis/nilfs2.git
+T:	git https://github.com/konis/nilfs2.git
 F:	Documentation/filesystems/nilfs2.rst
 F:	fs/nilfs2/
 F:	include/trace/events/nilfs2.h

arch/x86/include/asm/string_64.h

@@ -10,10 +10,13 @@
 /* Even with __builtin_ the compiler may decide to use the out of line
    function. */
 
+#if defined(__SANITIZE_MEMORY__) && defined(__NO_FORTIFY)
+#include <linux/kmsan_string.h>
+#endif
+
 #define __HAVE_ARCH_MEMCPY 1
-#if defined(__SANITIZE_MEMORY__)
+#if defined(__SANITIZE_MEMORY__) && defined(__NO_FORTIFY)
 #undef memcpy
-void *__msan_memcpy(void *dst, const void *src, size_t size);
 #define memcpy __msan_memcpy
 #else
 extern void *memcpy(void *to, const void *from, size_t len);
@@ -21,7 +24,7 @@ extern void *memcpy(void *to, const void *from, size_t len);
 extern void *__memcpy(void *to, const void *from, size_t len);
 
 #define __HAVE_ARCH_MEMSET
-#if defined(__SANITIZE_MEMORY__)
+#if defined(__SANITIZE_MEMORY__) && defined(__NO_FORTIFY)
 extern void *__msan_memset(void *s, int c, size_t n);
 #undef memset
 #define memset __msan_memset
@@ -67,7 +70,7 @@ static inline void *memset64(uint64_t *s, uint64_t v, size_t n)
 }
 
 #define __HAVE_ARCH_MEMMOVE
-#if defined(__SANITIZE_MEMORY__)
+#if defined(__SANITIZE_MEMORY__) && defined(__NO_FORTIFY)
 #undef memmove
 void *__msan_memmove(void *dest, const void *src, size_t len);
 #define memmove __msan_memmove

arch/x86/include/asm/uaccess.h

@@ -254,24 +254,25 @@ extern void __put_user_nocheck_8(void);
 #define __put_user_size(x, ptr, size, label)				\
 do {									\
 	__typeof__(*(ptr)) __x = (x); /* eval x once */			\
-	__chk_user_ptr(ptr);						\
+	__typeof__(ptr) __ptr = (ptr); /* eval ptr once */		\
+	__chk_user_ptr(__ptr);						\
 	switch (size) {							\
 	case 1:								\
-		__put_user_goto(__x, ptr, "b", "iq", label);		\
+		__put_user_goto(__x, __ptr, "b", "iq", label);		\
 		break;							\
 	case 2:								\
-		__put_user_goto(__x, ptr, "w", "ir", label);		\
+		__put_user_goto(__x, __ptr, "w", "ir", label);		\
 		break;							\
 	case 4:								\
-		__put_user_goto(__x, ptr, "l", "ir", label);		\
+		__put_user_goto(__x, __ptr, "l", "ir", label);		\
 		break;							\
 	case 8:								\
-		__put_user_goto_u64(__x, ptr, label);			\
+		__put_user_goto_u64(__x, __ptr, label);			\
 		break;							\
 	default:							\
 		__put_user_bad();					\
 	}								\
-	instrument_put_user(__x, ptr, size);				\
+	instrument_put_user(__x, __ptr, size);				\
 } while (0)
 
 #ifdef CONFIG_CC_HAS_ASM_GOTO_OUTPUT

arch/x86/purgatory/Makefile

@@ -26,6 +26,7 @@ GCOV_PROFILE	:= n
 KASAN_SANITIZE	:= n
 UBSAN_SANITIZE	:= n
 KCSAN_SANITIZE	:= n
+KMSAN_SANITIZE	:= n
 KCOV_INSTRUMENT := n
 
 # These are adjustments to the compiler flags used for objects that

fs/exec.c

@@ -1012,7 +1012,6 @@ static int exec_mmap(struct mm_struct *mm)
 	active_mm = tsk->active_mm;
 	tsk->active_mm = mm;
 	tsk->mm = mm;
-	lru_gen_add_mm(mm);
 	/*
 	 * This prevents preemption while active_mm is being loaded and
 	 * it and mm are being updated, which could cause problems for
@@ -1025,6 +1024,7 @@ static int exec_mmap(struct mm_struct *mm)
 	activate_mm(active_mm, mm);
 	if (IS_ENABLED(CONFIG_ARCH_WANT_IRQS_OFF_ACTIVATE_MM))
 		local_irq_enable();
+	lru_gen_add_mm(mm);
 	task_unlock(tsk);
 	lru_gen_use_mm(mm);
 	if (old_mm) {

fs/ext4/super.c

@@ -1741,10 +1741,6 @@ static const struct fs_parameter_spec ext4_param_specs[] = {
 
 #define DEFAULT_JOURNAL_IOPRIO (IOPRIO_PRIO_VALUE(IOPRIO_CLASS_BE, 3))
 
-static const char deprecated_msg[] =
-	"Mount option \"%s\" will be removed by %s\n"
-	"Contact linux-ext4@vger.kernel.org if you think we should keep it.\n";
-
 #define MOPT_SET	0x0001
 #define MOPT_CLEAR	0x0002
 #define MOPT_NOSUPPORT	0x0004

fs/squashfs/file.c

@@ -506,8 +506,9 @@ static int squashfs_readahead_fragment(struct page **page,
 		squashfs_i(inode)->fragment_size);
 	struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
 	unsigned int n, mask = (1 << (msblk->block_log - PAGE_SHIFT)) - 1;
+	int error = buffer->error;
 
-	if (buffer->error)
+	if (error)
 		goto out;
 
 	expected += squashfs_i(inode)->fragment_offset;
@@ -529,7 +530,7 @@ static int squashfs_readahead_fragment(struct page **page,
 
 out:
 	squashfs_cache_put(buffer);
-	return buffer->error;
+	return error;
 }
 
 static void squashfs_readahead(struct readahead_control *ractl)
@@ -557,6 +558,13 @@ static void squashfs_readahead(struct readahead_control *ractl)
 		int res, bsize;
 		u64 block = 0;
 		unsigned int expected;
+		struct page *last_page;
+
+		expected = start >> msblk->block_log == file_end ?
+			   (i_size_read(inode) & (msblk->block_size - 1)) :
+			    msblk->block_size;
+
+		max_pages = (expected + PAGE_SIZE - 1) >> PAGE_SHIFT;
 
 		nr_pages = __readahead_batch(ractl, pages, max_pages);
 		if (!nr_pages)
@@ -566,13 +574,10 @@ static void squashfs_readahead(struct readahead_control *ractl)
 			goto skip_pages;
 
 		index = pages[0]->index >> shift;
+
 		if ((pages[nr_pages - 1]->index >> shift) != index)
 			goto skip_pages;
 
-		expected = index == file_end ?
-			   (i_size_read(inode) & (msblk->block_size - 1)) :
-			    msblk->block_size;
-
 		if (index == file_end && squashfs_i(inode)->fragment_block !=
 						SQUASHFS_INVALID_BLK) {
 			res = squashfs_readahead_fragment(pages, nr_pages,
@@ -593,15 +598,15 @@ static void squashfs_readahead(struct readahead_control *ractl)
 
 		res = squashfs_read_data(inode->i_sb, block, bsize, NULL, actor);
 
-		squashfs_page_actor_free(actor);
+		last_page = squashfs_page_actor_free(actor);
 
 		if (res == expected) {
 			int bytes;
 
 			/* Last page (if present) may have trailing bytes not filled */
 			bytes = res % PAGE_SIZE;
-			if (pages[nr_pages - 1]->index == file_end && bytes)
-				memzero_page(pages[nr_pages - 1], bytes,
+			if (index == file_end && bytes && last_page)
+				memzero_page(last_page, bytes,
 					     PAGE_SIZE - bytes);
 
 			for (i = 0; i < nr_pages; i++) {

fs/squashfs/page_actor.c

@@ -71,11 +71,13 @@ static void *handle_next_page(struct squashfs_page_actor *actor)
 			(actor->next_index != actor->page[actor->next_page]->index)) {
 		actor->next_index++;
 		actor->returned_pages++;
+		actor->last_page = NULL;
 		return actor->alloc_buffer ? actor->tmp_buffer : ERR_PTR(-ENOMEM);
 	}
 
 	actor->next_index++;
 	actor->returned_pages++;
+	actor->last_page = actor->page[actor->next_page];
 	return actor->pageaddr = kmap_local_page(actor->page[actor->next_page++]);
 }
 
@@ -125,6 +127,7 @@ struct squashfs_page_actor *squashfs_page_actor_init_special(struct squashfs_sb_
 	actor->returned_pages = 0;
 	actor->next_index = page[0]->index & ~((1 << (msblk->block_log - PAGE_SHIFT)) - 1);
 	actor->pageaddr = NULL;
+	actor->last_page = NULL;
 	actor->alloc_buffer = msblk->decompressor->alloc_buffer;
 	actor->squashfs_first_page = direct_first_page;
 	actor->squashfs_next_page = direct_next_page;

fs/squashfs/page_actor.h

@@ -16,6 +16,7 @@ struct squashfs_page_actor {
 	void    *(*squashfs_first_page)(struct squashfs_page_actor *);
 	void    *(*squashfs_next_page)(struct squashfs_page_actor *);
 	void    (*squashfs_finish_page)(struct squashfs_page_actor *);
+	struct page *last_page;
 	int	pages;
 	int	length;
 	int	next_page;
@@ -29,10 +30,13 @@ extern struct squashfs_page_actor *squashfs_page_actor_init(void **buffer,
 extern struct squashfs_page_actor *squashfs_page_actor_init_special(
 				struct squashfs_sb_info *msblk,
 				struct page **page, int pages, int length);
-static inline void squashfs_page_actor_free(struct squashfs_page_actor *actor)
+static inline struct page *squashfs_page_actor_free(struct squashfs_page_actor *actor)
 {
+	struct page *last_page = actor->last_page;
+
 	kfree(actor->tmp_buffer);
 	kfree(actor);
+	return last_page;
 }
 static inline void *squashfs_first_page(struct squashfs_page_actor *actor)
 {

include/linux/fortify-string.h

@@ -43,11 +43,24 @@ extern __kernel_size_t __underlying_strlen(const char *p) __RENAME(strlen);
 extern char *__underlying_strncat(char *p, const char *q, __kernel_size_t count) __RENAME(strncat);
 extern char *__underlying_strncpy(char *p, const char *q, __kernel_size_t size) __RENAME(strncpy);
 #else
-#define __underlying_memchr	__builtin_memchr
-#define __underlying_memcmp	__builtin_memcmp
+
+#if defined(__SANITIZE_MEMORY__)
+/*
+ * For KMSAN builds all memcpy/memset/memmove calls should be replaced by the
+ * corresponding __msan_XXX functions.
+ */
+#include <linux/kmsan_string.h>
+#define __underlying_memcpy	__msan_memcpy
+#define __underlying_memmove	__msan_memmove
+#define __underlying_memset	__msan_memset
+#else
 #define __underlying_memcpy	__builtin_memcpy
 #define __underlying_memmove	__builtin_memmove
 #define __underlying_memset	__builtin_memset
+#endif
+
+#define __underlying_memchr	__builtin_memchr
+#define __underlying_memcmp	__builtin_memcmp
 #define __underlying_strcat	__builtin_strcat
 #define __underlying_strcpy	__builtin_strcpy
 #define __underlying_strlen	__builtin_strlen

include/linux/kmsan_string.h

+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * KMSAN string functions API used in other headers.
+ *
+ * Copyright (C) 2022 Google LLC
+ * Author: Alexander Potapenko <glider@google.com>
+ *
+ */
+#ifndef _LINUX_KMSAN_STRING_H
+#define _LINUX_KMSAN_STRING_H
+
+/*
+ * KMSAN overrides the default memcpy/memset/memmove implementations in the
+ * kernel, which requires having __msan_XXX function prototypes in several other
+ * headers. Keep them in one place instead of open-coding.
+ */
+void *__msan_memcpy(void *dst, const void *src, size_t size);
+void *__msan_memset(void *s, int c, size_t n);
+void *__msan_memmove(void *dest, const void *src, size_t len);
+
+#endif /* _LINUX_KMSAN_STRING_H */

include/linux/userfaultfd_k.h

@@ -146,9 +146,9 @@ static inline bool userfaultfd_armed(struct vm_area_struct *vma)
 static inline bool vma_can_userfault(struct vm_area_struct *vma,
 				     unsigned long vm_flags)
 {
-	if (vm_flags & VM_UFFD_MINOR)
-		return is_vm_hugetlb_page(vma) || vma_is_shmem(vma);
-
+	if ((vm_flags & VM_UFFD_MINOR) &&
+	    (!is_vm_hugetlb_page(vma) && !vma_is_shmem(vma)))
+		return false;
 #ifndef CONFIG_PTE_MARKER_UFFD_WP
 	/*
 	 * If user requested uffd-wp but not enabled pte markers for

ipc/msg.c

@@ -1329,11 +1329,11 @@ int msg_init_ns(struct ipc_namespace *ns)
 #ifdef CONFIG_IPC_NS
 void msg_exit_ns(struct ipc_namespace *ns)
 {
-	percpu_counter_destroy(&ns->percpu_msg_bytes);
-	percpu_counter_destroy(&ns->percpu_msg_hdrs);
 	free_ipcs(ns, &msg_ids(ns), freeque);
 	idr_destroy(&ns->ids[IPC_MSG_IDS].ipcs_idr);
 	rhashtable_destroy(&ns->ids[IPC_MSG_IDS].key_ht);
+	percpu_counter_destroy(&ns->percpu_msg_bytes);
+	percpu_counter_destroy(&ns->percpu_msg_hdrs);
 }
 #endif
 

lib/Kconfig.debug

@@ -400,8 +400,9 @@ config FRAME_WARN
 	default 1536 if (!64BIT && XTENSA)
 	default 1024 if !64BIT
 	default 2048 if 64BIT
+	default 0 if KMSAN
 	help
-	  Tell gcc to warn at build time for stack frames larger than this.
+	  Tell the compiler to warn at build time for stack frames larger than this.
 	  Setting this too low will cause a lot of warnings.
 	  Setting it to 0 disables the warning.
 

lib/maple_tree.c

@@ -2903,8 +2903,8 @@ static inline void *mtree_range_walk(struct ma_state *mas)
 	unsigned long max, min;
 	unsigned long prev_max, prev_min;
 
-	last = next = mas->node;
-	prev_min = min = mas->min;
+	next = mas->node;
+	min = mas->min;
 	max = mas->max;
 	do {
 		offset = 0;

mm/huge_memory.c

@@ -2462,7 +2462,7 @@ static void __split_huge_page_tail(struct page *head, int tail,
 	 * Fix up and warn once if private is unexpectedly set.
 	 */
 	if (!folio_test_swapcache(page_folio(head))) {
-		VM_WARN_ON_ONCE_PAGE(page_tail->private != 0, head);
+		VM_WARN_ON_ONCE_PAGE(page_tail->private != 0, page_tail);
 		page_tail->private = 0;
 	}
 

mm/kmemleak.c

@@ -1460,6 +1460,27 @@ static void scan_gray_list(void)
 	WARN_ON(!list_empty(&gray_list));
 }
 
+/*
+ * Conditionally call resched() in a object iteration loop while making sure
+ * that the given object won't go away without RCU read lock by performing a
+ * get_object() if !pinned.
+ *
+ * Return: false if can't do a cond_resched() due to get_object() failure
+ *	   true otherwise
+ */
+static bool kmemleak_cond_resched(struct kmemleak_object *object, bool pinned)
+{
+	if (!pinned && !get_object(object))
+		return false;
+
+	rcu_read_unlock();
+	cond_resched();
+	rcu_read_lock();
+	if (!pinned)
+		put_object(object);
+	return true;
+}
+
 /*
  * Scan data sections and all the referenced memory blocks allocated via the
  * kernel's standard allocators. This function must be called with the
@@ -1471,7 +1492,7 @@ static void kmemleak_scan(void)
 	struct zone *zone;
 	int __maybe_unused i;
 	int new_leaks = 0;
-	int loop1_cnt = 0;
+	int loop_cnt = 0;
 
 	jiffies_last_scan = jiffies;
 
@@ -1480,7 +1501,6 @@ static void kmemleak_scan(void)
 	list_for_each_entry_rcu(object, &object_list, object_list) {
 		bool obj_pinned = false;
 
-		loop1_cnt++;
 		raw_spin_lock_irq(&object->lock);
 #ifdef DEBUG
 		/*
@@ -1514,24 +1534,11 @@ static void kmemleak_scan(void)
 		raw_spin_unlock_irq(&object->lock);
 
 		/*
-		 * Do a cond_resched() to avoid soft lockup every 64k objects.
-		 * Make sure a reference has been taken so that the object
-		 * won't go away without RCU read lock.
+		 * Do a cond_resched() every 64k objects to avoid soft lockup.
 		 */
-		if (!(loop1_cnt & 0xffff)) {
-			if (!obj_pinned && !get_object(object)) {
-				/* Try the next object instead */
-				loop1_cnt--;
-				continue;
-			}
-
-			rcu_read_unlock();
-			cond_resched();
-			rcu_read_lock();
-
-			if (!obj_pinned)
-				put_object(object);
-		}
+		if (!(++loop_cnt & 0xffff) &&
+		    !kmemleak_cond_resched(object, obj_pinned))
+			loop_cnt--; /* Try again on next object */
 	}
 	rcu_read_unlock();
 
@@ -1598,7 +1605,15 @@ static void kmemleak_scan(void)
 	 * scan and color them gray until the next scan.
 	 */
 	rcu_read_lock();
+	loop_cnt = 0;
 	list_for_each_entry_rcu(object, &object_list, object_list) {
+		/*
+		 * Do a cond_resched() every 64k objects to avoid soft lockup.
+		 */
+		if (!(++loop_cnt & 0xffff) &&
+		    !kmemleak_cond_resched(object, false))
+			loop_cnt--;	/* Try again on next object */
+
 		/*
 		 * This is racy but we can save the overhead of lock/unlock
 		 * calls. The missed objects, if any, should be caught in
@@ -1632,7 +1647,15 @@ static void kmemleak_scan(void)
 	 * Scanning result reporting.
 	 */
 	rcu_read_lock();
+	loop_cnt = 0;
 	list_for_each_entry_rcu(object, &object_list, object_list) {
+		/*
+		 * Do a cond_resched() every 64k objects to avoid soft lockup.
+		 */
+		if (!(++loop_cnt & 0xffff) &&
+		    !kmemleak_cond_resched(object, false))
+			loop_cnt--;	/* Try again on next object */
+
 		/*
 		 * This is racy but we can save the overhead of lock/unlock
 		 * calls. The missed objects, if any, should be caught in

mm/kmsan/instrumentation.c

@@ -14,6 +14,7 @@
 
 #include "kmsan.h"
 #include <linux/gfp.h>
+#include <linux/kmsan_string.h>
 #include <linux/mm.h>
 #include <linux/uaccess.h>
 

mm/kmsan/shadow.c

@@ -167,6 +167,7 @@ void kmsan_copy_page_meta(struct page *dst, struct page *src)
 	__memcpy(origin_ptr_for(dst), origin_ptr_for(src), PAGE_SIZE);
 	kmsan_leave_runtime();
 }
+EXPORT_SYMBOL(kmsan_copy_page_meta);
 
 void kmsan_alloc_page(struct page *page, unsigned int order, gfp_t flags)
 {

mm/madvise.c

@@ -813,7 +813,14 @@ static bool madvise_dontneed_free_valid_vma(struct vm_area_struct *vma,
 	if (start & ~huge_page_mask(hstate_vma(vma)))
 		return false;
 
-	*end = ALIGN(*end, huge_page_size(hstate_vma(vma)));
+	/*
+	 * Madvise callers expect the length to be rounded up to PAGE_SIZE
+	 * boundaries, and may be unaware that this VMA uses huge pages.
+	 * Avoid unexpected data loss by rounding down the number of
+	 * huge pages freed.
+	 */
+	*end = ALIGN_DOWN(*end, huge_page_size(hstate_vma(vma)));
+
 	return true;
 }
 
@@ -828,6 +835,9 @@ static long madvise_dontneed_free(struct vm_area_struct *vma,
 	if (!madvise_dontneed_free_valid_vma(vma, start, &end, behavior))
 		return -EINVAL;
 
+	if (start == end)
+		return 0;
+
 	if (!userfaultfd_remove(vma, start, end)) {
 		*prev = NULL; /* mmap_lock has been dropped, prev is stale */
 

mm/memory-tiers.c

@@ -131,8 +131,8 @@ static void memory_tier_device_release(struct device *dev)
 	kfree(tier);
 }
 
-static ssize_t nodes_show(struct device *dev,
-			  struct device_attribute *attr, char *buf)
+static ssize_t nodelist_show(struct device *dev,
+			     struct device_attribute *attr, char *buf)
 {
 	int ret;
 	nodemask_t nmask;
@@ -143,10 +143,10 @@ static ssize_t nodes_show(struct device *dev,
 	mutex_unlock(&memory_tier_lock);
 	return ret;
 }
-static DEVICE_ATTR_RO(nodes);
+static DEVICE_ATTR_RO(nodelist);
 
 static struct attribute *memtier_dev_attrs[] = {
-	&dev_attr_nodes.attr,
+	&dev_attr_nodelist.attr,
 	NULL
 };
 

mm/migrate.c

@@ -1582,6 +1582,13 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page,
 	 */
 	list_splice(&ret_pages, from);
 
+	/*
+	 * Return 0 in case all subpages of fail-to-migrate THPs are
+	 * migrated successfully.
+	 */
+	if (list_empty(from))
+		rc = 0;
+
 	count_vm_events(PGMIGRATE_SUCCESS, nr_succeeded);
 	count_vm_events(PGMIGRATE_FAIL, nr_failed_pages);
 	count_vm_events(THP_MIGRATION_SUCCESS, nr_thp_succeeded);

mm/mmap.c

@@ -2852,6 +2852,9 @@ SYSCALL_DEFINE5(remap_file_pages, unsigned long, start, unsigned long, size,
 			if (next->vm_flags != vma->vm_flags)
 				goto out;
 
+			if (start + size <= next->vm_end)
+				break;
+
 			prev = next;
 		}
 

mm/page_alloc.c

@@ -807,6 +807,7 @@ static void prep_compound_tail(struct page *head, int tail_idx)
 
 	p->mapping = TAIL_MAPPING;
 	set_compound_head(p, head);
+	set_page_private(p, 0);
 }
 
 void prep_compound_page(struct page *page, unsigned int order)

mm/page_isolation.c

@@ -330,7 +330,7 @@ static int isolate_single_pageblock(unsigned long boundary_pfn, int flags,
 				      zone->zone_start_pfn);
 
 	if (skip_isolation) {
-		int mt = get_pageblock_migratetype(pfn_to_page(isolate_pageblock));
+		int mt __maybe_unused = get_pageblock_migratetype(pfn_to_page(isolate_pageblock));
 
 		VM_BUG_ON(!is_migrate_isolate(mt));
 	} else {

mm/shmem.c

@@ -2424,9 +2424,26 @@ int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
 
 		if (!zeropage) {	/* COPY */
 			page_kaddr = kmap_local_folio(folio, 0);
+			/*
+			 * The read mmap_lock is held here.  Despite the
+			 * mmap_lock being read recursive a deadlock is still
+			 * possible if a writer has taken a lock.  For example:
+			 *
+			 * process A thread 1 takes read lock on own mmap_lock
+			 * process A thread 2 calls mmap, blocks taking write lock
+			 * process B thread 1 takes page fault, read lock on own mmap lock
+			 * process B thread 2 calls mmap, blocks taking write lock
+			 * process A thread 1 blocks taking read lock on process B
+			 * process B thread 1 blocks taking read lock on process A
+			 *
+			 * Disable page faults to prevent potential deadlock
+			 * and retry the copy outside the mmap_lock.
+			 */
+			pagefault_disable();
 			ret = copy_from_user(page_kaddr,
 					     (const void __user *)src_addr,
 					     PAGE_SIZE);
+			pagefault_enable();
 			kunmap_local(page_kaddr);
 
 			/* fallback to copy_from_user outside mmap_lock */

mm/userfaultfd.c

@@ -157,11 +157,28 @@ static int mcopy_atomic_pte(struct mm_struct *dst_mm,
 		if (!page)
 			goto out;
 
-		page_kaddr = kmap_atomic(page);
+		page_kaddr = kmap_local_page(page);
+		/*
+		 * The read mmap_lock is held here.  Despite the
+		 * mmap_lock being read recursive a deadlock is still
+		 * possible if a writer has taken a lock.  For example:
+		 *
+		 * process A thread 1 takes read lock on own mmap_lock
+		 * process A thread 2 calls mmap, blocks taking write lock
+		 * process B thread 1 takes page fault, read lock on own mmap lock
+		 * process B thread 2 calls mmap, blocks taking write lock
+		 * process A thread 1 blocks taking read lock on process B
+		 * process B thread 1 blocks taking read lock on process A
+		 *
+		 * Disable page faults to prevent potential deadlock
+		 * and retry the copy outside the mmap_lock.
+		 */
+		pagefault_disable();
 		ret = copy_from_user(page_kaddr,
 				     (const void __user *) src_addr,
 				     PAGE_SIZE);
-		kunmap_atomic(page_kaddr);
+		pagefault_enable();
+		kunmap_local(page_kaddr);
 
 		/* fallback to copy_from_user outside mmap_lock */
 		if (unlikely(ret)) {
@@ -646,11 +663,11 @@ static __always_inline ssize_t __mcopy_atomic(struct mm_struct *dst_mm,
 			mmap_read_unlock(dst_mm);
 			BUG_ON(!page);
 
-			page_kaddr = kmap(page);
+			page_kaddr = kmap_local_page(page);
 			err = copy_from_user(page_kaddr,
 					     (const void __user *) src_addr,
 					     PAGE_SIZE);
-			kunmap(page);
+			kunmap_local(page_kaddr);
 			if (unlikely(err)) {
 				err = -EFAULT;
 				goto out;