Merge tag 'mm-hotfixes-stable-2025-05-10-14-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mmHEADmaster

Pull misc hotfixes from Andrew Morton:
 "22 hotfixes. 13 are cc:stable and the remainder address post-6.14
  issues or aren't considered necessary for -stable kernels.

  About half are for MM. Five OCFS2 fixes and a few MAINTAINERS updates"

* tag 'mm-hotfixes-stable-2025-05-10-14-23' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (22 commits)
  mm: fix folio_pte_batch() on XEN PV
  nilfs2: fix deadlock warnings caused by lock dependency in init_nilfs()
  mm/hugetlb: copy the CMA flag when demoting
  mm, swap: fix false warning for large allocation with !THP_SWAP
  selftests/mm: fix a build failure on powerpc
  selftests/mm: fix build break when compiling pkey_util.c
  mm: vmalloc: support more granular vrealloc() sizing
  tools/testing/selftests: fix guard region test tmpfs assumption
  ocfs2: stop quota recovery before disabling quotas
  ocfs2: implement handshaking with ocfs2 recovery thread
  ocfs2: switch osb->disable_recovery to enum
  mailmap: map Uwe's BayLibre addresses to a single one
  MAINTAINERS: add mm THP section
  mm/userfaultfd: fix uninitialized output field for -EAGAIN race
  selftests/mm: compaction_test: support platform with huge mount of memory
  MAINTAINERS: add core mm section
  ocfs2: fix panic in failed foilio allocation
  mm/huge_memory: fix dereferencing invalid pmd migration entry
  MAINTAINERS: add reverse mapping section
  x86: disable image size check for test builds
  ...

1 files changed, 24 insertions, 7 deletions

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 3ed720a787ec..2d7511654831 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -1940,7 +1940,7 @@ static inline void setup_vmalloc_vm(struct vm_struct *vm,
 {
 	vm->flags = flags;
 	vm->addr = (void *)va->va_start;
-	vm->size = va_size(va);
+	vm->size = vm->requested_size = va_size(va);
 	vm->caller = caller;
 	va->vm = vm;
 }
@@ -3133,6 +3133,7 @@ struct vm_struct *__get_vm_area_node(unsigned long size,
 
 	area->flags = flags;
 	area->caller = caller;
+	area->requested_size = requested_size;
 
 	va = alloc_vmap_area(size, align, start, end, node, gfp_mask, 0, area);
 	if (IS_ERR(va)) {
@@ -4063,6 +4064,8 @@ EXPORT_SYMBOL(vzalloc_node_noprof);
  */
 void *vrealloc_noprof(const void *p, size_t size, gfp_t flags)
 {
+	struct vm_struct *vm = NULL;
+	size_t alloced_size = 0;
 	size_t old_size = 0;
 	void *n;
 
@@ -4072,15 +4075,17 @@ void *vrealloc_noprof(const void *p, size_t size, gfp_t flags)
 	}
 
 	if (p) {
-		struct vm_struct *vm;
-
 		vm = find_vm_area(p);
 		if (unlikely(!vm)) {
 			WARN(1, "Trying to vrealloc() nonexistent vm area (%p)\n", p);
 			return NULL;
 		}
 
-		old_size = get_vm_area_size(vm);
+		alloced_size = get_vm_area_size(vm);
+		old_size = vm->requested_size;
+		if (WARN(alloced_size < old_size,
+			 "vrealloc() has mismatched area vs requested sizes (%p)\n", p))
+			return NULL;
 	}
 
 	/*
@@ -4088,14 +4093,26 @@ void *vrealloc_noprof(const void *p, size_t size, gfp_t flags)
 	 * would be a good heuristic for when to shrink the vm_area?
 	 */
 	if (size <= old_size) {
-		/* Zero out spare memory. */
-		if (want_init_on_alloc(flags))
+		/* Zero out "freed" memory. */
+		if (want_init_on_free())
 			memset((void *)p + size, 0, old_size - size);
+		vm->requested_size = size;
 		kasan_poison_vmalloc(p + size, old_size - size);
-		kasan_unpoison_vmalloc(p, size, KASAN_VMALLOC_PROT_NORMAL);
 		return (void *)p;
 	}
 
+	/*
+	 * We already have the bytes available in the allocation; use them.
+	 */
+	if (size <= alloced_size) {
+		kasan_unpoison_vmalloc(p + old_size, size - old_size,
+				       KASAN_VMALLOC_PROT_NORMAL);
+		/* Zero out "alloced" memory. */
+		if (want_init_on_alloc(flags))
+			memset((void *)p + old_size, 0, size - old_size);
+		vm->requested_size = size;
+	}
+
 	/* TODO: Grow the vm_area, i.e. allocate and map additional pages. */
 	n = __vmalloc_noprof(size, flags);
 	if (!n)