Merge tag 'mm-hotfixes-stable-2025-08-21-18-17' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "20 hotfixes. 10 are cc:stable and the remainder address post-6.16
  issues or aren't considered necessary for -stable kernels. 17 of these
  fixes are for MM.

  As usual, singletons all over the place, apart from a three-patch
  series of KHO followup work from Pasha which is actually also a bunch
  of singletons"

* tag 'mm-hotfixes-stable-2025-08-21-18-17' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  mm/mremap: fix WARN with uffd that has remap events disabled
  mm/damon/sysfs-schemes: put damos dests dir after removing its files
  mm/migrate: fix NULL movable_ops if CONFIG_ZSMALLOC=m
  mm/damon/core: fix damos_commit_filter not changing allow
  mm/memory-failure: fix infinite UCE for VM_PFNMAP pfn
  MAINTAINERS: mark MGLRU as maintained
  mm: rust: add page.rs to MEMORY MANAGEMENT - RUST
  iov_iter: iterate_folioq: fix handling of offset >= folio size
  selftests/damon: fix selftests by installing drgn related script
  .mailmap: add entry for Easwar Hariharan
  selftests/mm: add test for invalid multi VMA operations
  mm/mremap: catch invalid multi VMA moves earlier
  mm/mremap: allow multi-VMA move when filesystem uses thp_get_unmapped_area
  mm/damon/core: fix commit_ops_filters by using correct nth function
  tools/testing: add linux/args.h header and fix radix, VMA tests
  mm/debug_vm_pgtable: clear page table entries at destroy_args()
  squashfs: fix memory leak in squashfs_fill_super
  kho: warn if KHO is disabled due to an error
  kho: mm: don't allow deferred struct page with KHO
  kho: init new_physxa->phys_bits to fix lockdep

2 files changed, 26 insertions, 4 deletions

diff --git a/kernel/Kconfig.kexec b/kernel/Kconfig.kexec
index 2ee603a98813..1224dd937df0 100644
--- a/kernel/Kconfig.kexec
+++ b/kernel/Kconfig.kexec
@@ -97,6 +97,7 @@ config KEXEC_JUMP
 config KEXEC_HANDOVER
 	bool "kexec handover"
 	depends on ARCH_SUPPORTS_KEXEC_HANDOVER && ARCH_SUPPORTS_KEXEC_FILE
+	depends on !DEFERRED_STRUCT_PAGE_INIT
 	select MEMBLOCK_KHO_SCRATCH
 	select KEXEC_FILE
 	select DEBUG_FS
diff --git a/kernel/kexec_handover.c b/kernel/kexec_handover.c
index e49743ae52c5..ecd1ac210dbd 100644
--- a/kernel/kexec_handover.c
+++ b/kernel/kexec_handover.c
@@ -144,14 +144,34 @@ static int __kho_preserve_order(struct kho_mem_track *track, unsigned long pfn,
 				unsigned int order)
 {
 	struct kho_mem_phys_bits *bits;
-	struct kho_mem_phys *physxa;
+	struct kho_mem_phys *physxa, *new_physxa;
 	const unsigned long pfn_high = pfn >> order;
 
 	might_sleep();
 
-	physxa = xa_load_or_alloc(&track->orders, order, sizeof(*physxa));
-	if (IS_ERR(physxa))
-		return PTR_ERR(physxa);
+	physxa = xa_load(&track->orders, order);
+	if (!physxa) {
+		int err;
+
+		new_physxa = kzalloc(sizeof(*physxa), GFP_KERNEL);
+		if (!new_physxa)
+			return -ENOMEM;
+
+		xa_init(&new_physxa->phys_bits);
+		physxa = xa_cmpxchg(&track->orders, order, NULL, new_physxa,
+				    GFP_KERNEL);
+
+		err = xa_err(physxa);
+		if (err || physxa) {
+			xa_destroy(&new_physxa->phys_bits);
+			kfree(new_physxa);
+
+			if (err)
+				return err;
+		} else {
+			physxa = new_physxa;
+		}
+	}
 
 	bits = xa_load_or_alloc(&physxa->phys_bits, pfn_high / PRESERVE_BITS,
 				sizeof(*bits));
@@ -544,6 +564,7 @@ err_free_scratch_areas:
 err_free_scratch_desc:
 	memblock_free(kho_scratch, kho_scratch_cnt * sizeof(*kho_scratch));
 err_disable_kho:
+	pr_warn("Failed to reserve scratch area, disabling kexec handover\n");
 	kho_enable = false;
 }