ANDROID: mm: add a field to store names for private anonymous memory

Userspace processes often have multiple allocators that each do
anonymous mmaps to get memory.  When examining memory usage of
individual processes or systems as a whole, it is useful to be
able to break down the various heaps that were allocated by
each layer and examine their size, RSS, and physical memory
usage.

This patch adds a user pointer to the shared union in
vm_area_struct that points to a null terminated string inside
the user process containing a name for the vma.  vmas that
point to the same address will be merged, but vmas that
point to equivalent strings at different addresses will
not be merged.

Userspace can set the name for a region of memory by calling
prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, start, len, (unsigned long)name);
Setting the name to NULL clears it.

The names of named anonymous vmas are shown in /proc/pid/maps
as [anon:<name>] and in /proc/pid/smaps in a new "Name" field
that is only present for named vmas.  If the userspace pointer
is no longer valid all or part of the name will be replaced
with "<fault>".

The idea to store a userspace pointer to reduce the complexity
within mm (at the expense of the complexity of reading
/proc/pid/mem) came from Dave Hansen.  This results in no
runtime overhead in the mm subsystem other than comparing
the anon_name pointers when considering vma merging.  The pointer
is stored in a union with fieds that are only used on file-backed
mappings, so it does not increase memory usage.

Includes fix from Jed Davis <jld@mozilla.com> for typo in
prctl_set_vma_anon_name, which could attempt to set the name
across two vmas at the same time due to a typo, which might
corrupt the vma list.  Fix it to use tmp instead of end to limit
the name setting to a single vma at a time.

Bug: 120441514
Change-Id: I9aa7b6b5ef536cd780599ba4e2fba8ceebe8b59f
Signed-off-by: Dmitry Shmidt <dimitrysh@google.com>
[AmitP: Fix get_user_pages_remote() call to align with upstream commit
        5b56d49fc31d ("mm: add locked parameter to get_user_pages_remote()")]
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>
Rebased for 5.3 kernel
Signed-off-by: Joonas Kylmälä <joonas.kylmala@iki.fi>

12 files changed, 282 insertions, 29 deletions

diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index 99ca040e3f90..4579d1452f89 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -415,6 +415,8 @@ is not associated with a file:
  [stack]                  = the stack of the main process
  [vdso]                   = the "virtual dynamic shared object",
                             the kernel system call handler
+ [anon:<name>]            = an anonymous mapping that has been
+                            named by userspace
 
  or if empty, the mapping is anonymous.
 
@@ -447,6 +449,7 @@ MMUPageSize:           4 kB
 Locked:                0 kB
 THPeligible:           0
 VmFlags: rd ex mr mw me dw
+Name:           name from userspace
 
 The first of these lines shows the same information as is displayed for the
 mapping in /proc/PID/maps.  Following lines show the size of the mapping
@@ -526,6 +529,9 @@ be vanished or the reverse -- new added. Interpretation of their meaning
 might change in future as well. So each consumer of these flags has to
 follow each specific kernel version for the exact semantic.
 
+The "Name" field will only be present on a mapping that has been named by
+userspace, and will show the name passed in by userspace.
+
 This file is only present if the CONFIG_MMU kernel configuration option is
 enabled.
 
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 731642e0f5a0..3275002c23fc 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -123,6 +123,56 @@ static void release_task_mempolicy(struct proc_maps_private *priv)
 }
 #endif
 
+static void seq_print_vma_name(struct seq_file *m, struct vm_area_struct *vma)
+{
+	const char __user *name = vma_get_anon_name(vma);
+	struct mm_struct *mm = vma->vm_mm;
+
+	unsigned long page_start_vaddr;
+	unsigned long page_offset;
+	unsigned long num_pages;
+	unsigned long max_len = NAME_MAX;
+	int i;
+
+	page_start_vaddr = (unsigned long)name & PAGE_MASK;
+	page_offset = (unsigned long)name - page_start_vaddr;
+	num_pages = DIV_ROUND_UP(page_offset + max_len, PAGE_SIZE);
+
+	seq_puts(m, "[anon:");
+
+	for (i = 0; i < num_pages; i++) {
+		int len;
+		int write_len;
+		const char *kaddr;
+		long pages_pinned;
+		struct page *page;
+
+		pages_pinned = get_user_pages_remote(current, mm,
+				page_start_vaddr, 1, 0, &page, NULL, NULL);
+		if (pages_pinned < 1) {
+			seq_puts(m, "<fault>]");
+			return;
+		}
+
+		kaddr = (const char *)kmap(page);
+		len = min(max_len, PAGE_SIZE - page_offset);
+		write_len = strnlen(kaddr + page_offset, len);
+		seq_write(m, kaddr + page_offset, write_len);
+		kunmap(page);
+		put_page(page);
+
+		/* if strnlen hit a null terminator then we're done */
+		if (write_len != len)
+			break;
+
+		max_len -= len;
+		page_offset = 0;
+		page_start_vaddr += PAGE_SIZE;
+	}
+
+	seq_putc(m, ']');
+}
+
 static void vma_stop(struct proc_maps_private *priv)
 {
 	struct mm_struct *mm = priv->mm;
@@ -348,8 +398,15 @@ show_map_vma(struct seq_file *m, struct vm_area_struct *vma)
 			goto done;
 		}
 
-		if (is_stack(vma))
+		if (is_stack(vma)) {
 			name = "[stack]";
+			goto done;
+		}
+
+		if (vma_get_anon_name(vma)) {
+			seq_pad(m, ' ');
+			seq_print_vma_name(m, vma);
+		}
 	}
 
 done:
@@ -824,6 +881,11 @@ static int show_smap(struct seq_file *m, void *v)
 	smap_gather_stats(vma, &mss);
 
 	show_map_vma(m, vma);
+	if (vma_get_anon_name(vma)) {
+		seq_puts(m, "Name:           ");
+		seq_print_vma_name(m, vma);
+		seq_putc(m, '\n');
+	}
 
 	SEQ_PUT_DEC("Size:           ", vma->vm_end - vma->vm_start);
 	SEQ_PUT_DEC(" kB\nKernelPageSize: ", vma_kernel_pagesize(vma));
diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
index fe6d804a38dc..0c98d376d246 100644
--- a/fs/userfaultfd.c
+++ b/fs/userfaultfd.c
@@ -911,8 +911,10 @@ static int userfaultfd_release(struct inode *inode, struct file *file)
 			prev = vma_merge(mm, prev, vma->vm_start, vma->vm_end,
 					 new_flags, vma->anon_vma,
 					 vma->vm_file, vma->vm_pgoff,
-					 vma_policy(vma),
-					 NULL_VM_UFFD_CTX);
+					 vma_policy(vma),	
+					 NULL_VM_UFFD_CTX,
+					 vma_get_anon_name(vma));
+            
 			if (prev)
 				vma = prev;
 			else
@@ -1462,7 +1464,8 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx,
 		prev = vma_merge(mm, prev, start, vma_end, new_flags,
 				 vma->anon_vma, vma->vm_file, vma->vm_pgoff,
 				 vma_policy(vma),
-				 ((struct vm_userfaultfd_ctx){ ctx }));
+				 ((struct vm_userfaultfd_ctx){ ctx }),
+				 vma_get_anon_name(vma));
 		if (prev) {
 			vma = prev;
 			goto next;
@@ -1624,7 +1627,8 @@ static int userfaultfd_unregister(struct userfaultfd_ctx *ctx,
 		prev = vma_merge(mm, prev, start, vma_end, new_flags,
 				 vma->anon_vma, vma->vm_file, vma->vm_pgoff,
 				 vma_policy(vma),
-				 NULL_VM_UFFD_CTX);
+				 NULL_VM_UFFD_CTX,
+				 vma_get_anon_name(vma));
 		if (prev) {
 			vma = prev;
 			goto next;
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 0334ca97c584..9fd371a63cab 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2301,7 +2301,7 @@ static inline int vma_adjust(struct vm_area_struct *vma, unsigned long start,
 extern struct vm_area_struct *vma_merge(struct mm_struct *,
 	struct vm_area_struct *prev, unsigned long addr, unsigned long end,
 	unsigned long vm_flags, struct anon_vma *, struct file *, pgoff_t,
-	struct mempolicy *, struct vm_userfaultfd_ctx);
+	struct mempolicy *, struct vm_userfaultfd_ctx, const char __user *);
 extern struct anon_vma *find_mergeable_anon_vma(struct vm_area_struct *);
 extern int __split_vma(struct mm_struct *, struct vm_area_struct *,
 	unsigned long addr, int new_below);
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 6a7a1083b6fb..2b09663f0db6 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -313,11 +313,18 @@ struct vm_area_struct {
 	/*
 	 * For areas with an address space and backing store,
 	 * linkage into the address_space->i_mmap interval tree.
+	 *
+	 * For private anonymous mappings, a pointer to a null terminated string
+	 * in the user process containing the name given to the vma, or NULL
+	 * if unnamed.
 	 */
-	struct {
-		struct rb_node rb;
-		unsigned long rb_subtree_last;
-	} shared;
+	union {
+		struct {
+			struct rb_node rb;
+			unsigned long rb_subtree_last;
+		} shared;
+		const char __user *anon_name;
+	};
 
 	/*
 	 * A file's MAP_PRIVATE vma can be in both i_mmap tree and anon_vma
@@ -746,4 +753,13 @@ typedef struct {
 	unsigned long val;
 } swp_entry_t;
 
+/* Return the name for an anonymous mapping or NULL for a file-backed mapping */
+static inline const char __user *vma_get_anon_name(struct vm_area_struct *vma)
+{
+	if (vma->vm_file)
+		return NULL;
+
+	return vma->anon_name;
+}
+
 #endif /* _LINUX_MM_TYPES_H */
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index 094bb03b9cc2..e057eddb572f 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -229,4 +229,7 @@ struct prctl_mm_map {
 # define PR_PAC_APDBKEY			(1UL << 3)
 # define PR_PAC_APGAKEY			(1UL << 4)
 
+#define PR_SET_VMA		0x53564d41
+# define PR_SET_VMA_ANON_NAME		0
+
 #endif /* _LINUX_PRCTL_H */
diff --git a/kernel/sys.c b/kernel/sys.c
index 2969304c29fe..54f8fabc58e4 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -42,6 +42,8 @@
 #include <linux/syscore_ops.h>
 #include <linux/version.h>
 #include <linux/ctype.h>
+#include <linux/mm.h>
+#include <linux/mempolicy.h>
 
 #include <linux/compat.h>
 #include <linux/syscalls.h>
@@ -2269,6 +2271,153 @@ int __weak arch_prctl_spec_ctrl_set(struct task_struct *t, unsigned long which,
 	return -EINVAL;
 }
 
+#ifdef CONFIG_MMU
+static int prctl_update_vma_anon_name(struct vm_area_struct *vma,
+		struct vm_area_struct **prev,
+		unsigned long start, unsigned long end,
+		const char __user *name_addr)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	int error = 0;
+	pgoff_t pgoff;
+
+	if (name_addr == vma_get_anon_name(vma)) {
+		*prev = vma;
+		goto out;
+	}
+
+	pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
+	*prev = vma_merge(mm, *prev, start, end, vma->vm_flags, vma->anon_vma,
+				vma->vm_file, pgoff, vma_policy(vma),
+				vma->vm_userfaultfd_ctx, name_addr);
+	if (*prev) {
+		vma = *prev;
+		goto success;
+	}
+
+	*prev = vma;
+
+	if (start != vma->vm_start) {
+		error = split_vma(mm, vma, start, 1);
+		if (error)
+			goto out;
+	}
+
+	if (end != vma->vm_end) {
+		error = split_vma(mm, vma, end, 0);
+		if (error)
+			goto out;
+	}
+
+success:
+	if (!vma->vm_file)
+		vma->anon_name = name_addr;
+
+out:
+	if (error == -ENOMEM)
+		error = -EAGAIN;
+	return error;
+}
+
+static int prctl_set_vma_anon_name(unsigned long start, unsigned long end,
+			unsigned long arg)
+{
+	unsigned long tmp;
+	struct vm_area_struct *vma, *prev;
+	int unmapped_error = 0;
+	int error = -EINVAL;
+
+	/*
+	 * If the interval [start,end) covers some unmapped address
+	 * ranges, just ignore them, but return -ENOMEM at the end.
+	 * - this matches the handling in madvise.
+	 */
+	vma = find_vma_prev(current->mm, start, &prev);
+	if (vma && start > vma->vm_start)
+		prev = vma;
+
+	for (;;) {
+		/* Still start < end. */
+		error = -ENOMEM;
+		if (!vma)
+			return error;
+
+		/* Here start < (end|vma->vm_end). */
+		if (start < vma->vm_start) {
+			unmapped_error = -ENOMEM;
+			start = vma->vm_start;
+			if (start >= end)
+				return error;
+		}
+
+		/* Here vma->vm_start <= start < (end|vma->vm_end) */
+		tmp = vma->vm_end;
+		if (end < tmp)
+			tmp = end;
+
+		/* Here vma->vm_start <= start < tmp <= (end|vma->vm_end). */
+		error = prctl_update_vma_anon_name(vma, &prev, start, tmp,
+				(const char __user *)arg);
+		if (error)
+			return error;
+		start = tmp;
+		if (prev && start < prev->vm_end)
+			start = prev->vm_end;
+		error = unmapped_error;
+		if (start >= end)
+			return error;
+		if (prev)
+			vma = prev->vm_next;
+		else	/* madvise_remove dropped mmap_sem */
+			vma = find_vma(current->mm, start);
+	}
+}
+
+static int prctl_set_vma(unsigned long opt, unsigned long start,
+		unsigned long len_in, unsigned long arg)
+{
+	struct mm_struct *mm = current->mm;
+	int error;
+	unsigned long len;
+	unsigned long end;
+
+	if (start & ~PAGE_MASK)
+		return -EINVAL;
+	len = (len_in + ~PAGE_MASK) & PAGE_MASK;
+
+	/* Check to see whether len was rounded up from small -ve to zero */
+	if (len_in && !len)
+		return -EINVAL;
+
+	end = start + len;
+	if (end < start)
+		return -EINVAL;
+
+	if (end == start)
+		return 0;
+
+	down_write(&mm->mmap_sem);
+
+	switch (opt) {
+	case PR_SET_VMA_ANON_NAME:
+		error = prctl_set_vma_anon_name(start, end, arg);
+		break;
+	default:
+		error = -EINVAL;
+	}
+
+	up_write(&mm->mmap_sem);
+
+	return error;
+}
+#else /* CONFIG_MMU */
+static int prctl_set_vma(unsigned long opt, unsigned long start,
+		unsigned long len_in, unsigned long arg)
+{
+	return -EINVAL;
+}
+#endif
+
 SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
 		unsigned long, arg4, unsigned long, arg5)
 {
@@ -2487,6 +2636,9 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
 			return -EINVAL;
 		error = arch_prctl_spec_ctrl_set(me, arg2, arg3);
 		break;
+	case PR_SET_VMA:
+		error = prctl_set_vma(arg2, arg3, arg4, arg5);
+		break;
 	case PR_PAC_RESET_KEYS:
 		if (arg3 || arg4 || arg5)
 			return -EINVAL;
diff --git a/mm/madvise.c b/mm/madvise.c
index 968df3aa069f..b733c33c975a 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -138,7 +138,7 @@ static long madvise_behavior(struct vm_area_struct *vma,
 	pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
 	*prev = vma_merge(mm, *prev, start, end, new_flags, vma->anon_vma,
 			  vma->vm_file, pgoff, vma_policy(vma),
-			  vma->vm_userfaultfd_ctx);
+			  vma->vm_userfaultfd_ctx, vma_get_anon_name(vma));
 	if (*prev) {
 		vma = *prev;
 		goto success;
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 65e0874fce17..460282a8e4fe 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -758,7 +758,8 @@ static int mbind_range(struct mm_struct *mm, unsigned long start,
 			((vmstart - vma->vm_start) >> PAGE_SHIFT);
 		prev = vma_merge(mm, prev, vmstart, vmend, vma->vm_flags,
 				 vma->anon_vma, vma->vm_file, pgoff,
-				 new_pol, vma->vm_userfaultfd_ctx);
+				 new_pol, vma->vm_userfaultfd_ctx,
+				 vma_get_anon_name(vma));
 		if (prev) {
 			vma = prev;
 			next = vma->vm_next;
diff --git a/mm/mlock.c b/mm/mlock.c
index a90099da4fb4..25d326f1009d 100644
--- a/mm/mlock.c
+++ b/mm/mlock.c
@@ -535,7 +535,7 @@ static int mlock_fixup(struct vm_area_struct *vma, struct vm_area_struct **prev,
 	pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
 	*prev = vma_merge(mm, *prev, start, end, newflags, vma->anon_vma,
 			  vma->vm_file, pgoff, vma_policy(vma),
-			  vma->vm_userfaultfd_ctx);
+			  vma->vm_userfaultfd_ctx, vma_get_anon_name(vma));
 	if (*prev) {
 		vma = *prev;
 		goto success;
diff --git a/mm/mmap.c b/mm/mmap.c
index 7e8c3e8ae75f..51cd78b7c53b 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -1008,7 +1008,8 @@ again:
  */
 static inline int is_mergeable_vma(struct vm_area_struct *vma,
 				struct file *file, unsigned long vm_flags,
-				struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
+				struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
+				const char __user *anon_name)
 {
 	/*
 	 * VM_SOFTDIRTY should not prevent from VMA merging, if we
@@ -1026,6 +1027,8 @@ static inline int is_mergeable_vma(struct vm_area_struct *vma,
 		return 0;
 	if (!is_mergeable_vm_userfaultfd_ctx(vma, vm_userfaultfd_ctx))
 		return 0;
+	if (vma_get_anon_name(vma) != anon_name)
+		return 0;
 	return 1;
 }
 
@@ -1058,9 +1061,10 @@ static int
 can_vma_merge_before(struct vm_area_struct *vma, unsigned long vm_flags,
 		     struct anon_vma *anon_vma, struct file *file,
 		     pgoff_t vm_pgoff,
-		     struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
+		     struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
+		     const char __user *anon_name)
 {
-	if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx) &&
+	if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) &&
 	    is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
 		if (vma->vm_pgoff == vm_pgoff)
 			return 1;
@@ -1079,9 +1083,10 @@ static int
 can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
 		    struct anon_vma *anon_vma, struct file *file,
 		    pgoff_t vm_pgoff,
-		    struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
+		    struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
+		    const char __user *anon_name)
 {
-	if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx) &&
+	if (is_mergeable_vma(vma, file, vm_flags, vm_userfaultfd_ctx, anon_name) &&
 	    is_mergeable_anon_vma(anon_vma, vma->anon_vma, vma)) {
 		pgoff_t vm_pglen;
 		vm_pglen = vma_pages(vma);
@@ -1092,9 +1097,9 @@ can_vma_merge_after(struct vm_area_struct *vma, unsigned long vm_flags,
 }
 
 /*
- * Given a mapping request (addr,end,vm_flags,file,pgoff), figure out
- * whether that can be merged with its predecessor or its successor.
- * Or both (it neatly fills a hole).
+ * Given a mapping request (addr,end,vm_flags,file,pgoff,anon_name),
+ * figure out whether that can be merged with its predecessor or its
+ * successor.  Or both (it neatly fills a hole).
  *
  * In most cases - when called for mmap, brk or mremap - [addr,end) is
  * certain not to be mapped by the time vma_merge is called; but when
@@ -1136,7 +1141,8 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
 			unsigned long end, unsigned long vm_flags,
 			struct anon_vma *anon_vma, struct file *file,
 			pgoff_t pgoff, struct mempolicy *policy,
-			struct vm_userfaultfd_ctx vm_userfaultfd_ctx)
+			struct vm_userfaultfd_ctx vm_userfaultfd_ctx,
+			const char __user *anon_name)
 {
 	pgoff_t pglen = (end - addr) >> PAGE_SHIFT;
 	struct vm_area_struct *area, *next;
@@ -1169,7 +1175,8 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
 			mpol_equal(vma_policy(prev), policy) &&
 			can_vma_merge_after(prev, vm_flags,
 					    anon_vma, file, pgoff,
-					    vm_userfaultfd_ctx)) {
+					    vm_userfaultfd_ctx,
+					    anon_name)) {
 		/*
 		 * OK, it can.  Can we now merge in the successor as well?
 		 */
@@ -1178,7 +1185,8 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
 				can_vma_merge_before(next, vm_flags,
 						     anon_vma, file,
 						     pgoff+pglen,
-						     vm_userfaultfd_ctx) &&
+						     vm_userfaultfd_ctx,
+						     anon_name) &&
 				is_mergeable_anon_vma(prev->anon_vma,
 						      next->anon_vma, NULL)) {
 							/* cases 1, 6 */
@@ -1201,7 +1209,8 @@ struct vm_area_struct *vma_merge(struct mm_struct *mm,
 			mpol_equal(policy, vma_policy(next)) &&
 			can_vma_merge_before(next, vm_flags,
 					     anon_vma, file, pgoff+pglen,
-					     vm_userfaultfd_ctx)) {
+					     vm_userfaultfd_ctx,
+					     anon_name)) {
 		if (prev && addr < prev->vm_end)	/* case 4 */
 			err = __vma_adjust(prev, prev->vm_start,
 					 addr, prev->vm_pgoff, NULL, next);
@@ -1746,7 +1755,7 @@ unsigned long mmap_region(struct file *file, unsigned long addr,
 	 * Can we just expand an old mapping?
 	 */
 	vma = vma_merge(mm, prev, addr, addr + len, vm_flags,
-			NULL, file, pgoff, NULL, NULL_VM_UFFD_CTX);
+			NULL, file, pgoff, NULL, NULL_VM_UFFD_CTX, NULL);
 	if (vma)
 		goto out;
 
@@ -3025,7 +3034,7 @@ static int do_brk_flags(unsigned long addr, unsigned long len, unsigned long fla
 
 	/* Can we just expand an old private anonymous mapping? */
 	vma = vma_merge(mm, prev, addr, addr + len, flags,
-			NULL, NULL, pgoff, NULL, NULL_VM_UFFD_CTX);
+			NULL, NULL, pgoff, NULL, NULL_VM_UFFD_CTX, NULL);
 	if (vma)
 		goto out;
 
@@ -3223,7 +3232,7 @@ struct vm_area_struct *copy_vma(struct vm_area_struct **vmap,
 		return NULL;	/* should never get here */
 	new_vma = vma_merge(mm, prev, addr, addr + len, vma->vm_flags,
 			    vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
-			    vma->vm_userfaultfd_ctx);
+			    vma->vm_userfaultfd_ctx, vma_get_anon_name(vma));
 	if (new_vma) {
 		/*
 		 * Source vma may have been merged into new_vma
diff --git a/mm/mprotect.c b/mm/mprotect.c
index bf38dfbbb4b4..9b19034440bb 100644
--- a/mm/mprotect.c
+++ b/mm/mprotect.c
@@ -400,7 +400,7 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev,
 	pgoff = vma->vm_pgoff + ((start - vma->vm_start) >> PAGE_SHIFT);
 	*pprev = vma_merge(mm, *pprev, start, end, newflags,
 			   vma->anon_vma, vma->vm_file, pgoff, vma_policy(vma),
-			   vma->vm_userfaultfd_ctx);
+			   vma->vm_userfaultfd_ctx, vma_get_anon_name(vma));
 	if (*pprev) {
 		vma = *pprev;
 		VM_WARN_ON((vma->vm_flags ^ newflags) & ~VM_SOFTDIRTY);