diff --git a/arch/x86/mm/pat/memtype.c b/arch/x86/mm/pat/memtype.c
index feb8cc6a12bf..3a9e6dd58e2f 100644
--- a/arch/x86/mm/pat/memtype.c
+++ b/arch/x86/mm/pat/memtype.c
@@ -984,27 +984,54 @@ static int get_pat_info(struct vm_area_struct *vma, resource_size_t *paddr,
 	return -EINVAL;
 }
 
-/*
- * track_pfn_copy is called when vma that is covering the pfnmap gets
- * copied through copy_page_range().
- *
- * If the vma has a linear pfn mapping for the entire range, we get the prot
- * from pte and reserve the entire vma range with single reserve_pfn_range call.
- */
-int track_pfn_copy(struct vm_area_struct *vma)
+int track_pfn_copy(struct vm_area_struct *dst_vma,
+		struct vm_area_struct *src_vma)
 {
+	const unsigned long vma_size = src_vma->vm_end - src_vma->vm_start;
 	resource_size_t paddr;
-	unsigned long vma_size = vma->vm_end - vma->vm_start;
 	pgprot_t pgprot;
+	int rc;
 
-	if (vma->vm_flags & VM_PAT) {
-		if (get_pat_info(vma, &paddr, &pgprot))
-			return -EINVAL;
-		/* reserve the whole chunk covered by vma. */
-		return reserve_pfn_range(paddr, vma_size, &pgprot, 1);
+	if (!(src_vma->vm_flags & VM_PAT))
+		return 0;
+
+	/*
+	 * Duplicate the PAT information for the dst VMA based on the src
+	 * VMA.
+	 */
+	if (get_pat_info(src_vma, &paddr, &pgprot))
+		return -EINVAL;
+	rc = reserve_pfn_range(paddr, vma_size, &pgprot, 1);
+	if (!rc)
+		/* Reservation for the destination VMA succeeded. */
+		vm_flags_set(dst_vma, VM_PAT);
+	return rc;
+}
+
+void untrack_pfn_copy(struct vm_area_struct *dst_vma,
+		struct vm_area_struct *src_vma)
+{
+	resource_size_t paddr;
+	unsigned long size;
+
+	if (!(dst_vma->vm_flags & VM_PAT))
+		return;
+
+	/*
+	 * As the page tables might not have been copied yet, the PAT
+	 * information is obtained from the src VMA, just like during
+	 * track_pfn_copy().
+	 */
+	if (get_pat_info(src_vma, &paddr, NULL)) {
+		size = src_vma->vm_end - src_vma->vm_start;
+		free_pfn_range(paddr, size);
 	}
 
-	return 0;
+	/*
+	 * Reservation was freed, any copied page tables will get cleaned
+	 * up later, but without getting PAT involved again.
+	 */
+	vm_flags_clear(dst_vma, VM_PAT);
 }
 
 /*
@@ -1095,15 +1122,6 @@ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
 	}
 }
 
-/*
- * untrack_pfn_clear is called if the following situation fits:
- *
- * 1) while mremapping a pfnmap for a new region,  with the old vma after
- * its pfnmap page table has been removed.  The new vma has a new pfnmap
- * to the same pfn & cache type with VM_PAT set.
- * 2) while duplicating vm area, the new vma fails to copy the pgtable from
- * old vma.
- */
 void untrack_pfn_clear(struct vm_area_struct *vma)
 {
 	vm_flags_clear(vma, VM_PAT);
diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index e8b2ac6bd2ae..616707b4ecb8 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -1518,14 +1518,24 @@ static inline void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 }
 
 /*
- * track_pfn_copy is called when vma that is covering the pfnmap gets
- * copied through copy_page_range().
+ * track_pfn_copy is called when a VM_PFNMAP VMA is about to get the page
+ * tables copied during copy_page_range().
  */
-static inline int track_pfn_copy(struct vm_area_struct *vma)
+static inline int track_pfn_copy(struct vm_area_struct *dst_vma,
+		struct vm_area_struct *src_vma)
 {
 	return 0;
 }
 
+/*
+ * untrack_pfn_copy is called when a VM_PFNMAP VMA failed to copy during
+ * copy_page_range(), but after track_pfn_copy() was already called.
+ */
+static inline void untrack_pfn_copy(struct vm_area_struct *dst_vma,
+		struct vm_area_struct *src_vma)
+{
+}
+
 /*
  * untrack_pfn is called while unmapping a pfnmap for a region.
  * untrack can be called for a specific region indicated by pfn and size or
@@ -1538,8 +1548,10 @@ static inline void untrack_pfn(struct vm_area_struct *vma,
 }
 
 /*
- * untrack_pfn_clear is called while mremapping a pfnmap for a new region
- * or fails to copy pgtable during duplicate vm area.
+ * untrack_pfn_clear is called in the following cases on a VM_PFNMAP VMA:
+ *
+ * 1) During mremap() on the src VMA after the page tables were moved.
+ * 2) During fork() on the dst VMA, immediately after duplicating the src VMA.
  */
 static inline void untrack_pfn_clear(struct vm_area_struct *vma)
 {
@@ -1550,7 +1562,10 @@ extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot,
 			   unsigned long size);
 extern void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot,
 			     pfn_t pfn);
-extern int track_pfn_copy(struct vm_area_struct *vma);
+extern int track_pfn_copy(struct vm_area_struct *dst_vma,
+		struct vm_area_struct *src_vma);
+extern void untrack_pfn_copy(struct vm_area_struct *dst_vma,
+		struct vm_area_struct *src_vma);
 extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn,
 			unsigned long size, bool mm_wr_locked);
 extern void untrack_pfn_clear(struct vm_area_struct *vma);
diff --git a/kernel/fork.c b/kernel/fork.c
index 89ceb4a68af2..02a7a8b44107 100644
--- a/kernel/fork.c
+++ b/kernel/fork.c
@@ -504,6 +504,10 @@ struct vm_area_struct *vm_area_dup(struct vm_area_struct *orig)
 	vma_numab_state_init(new);
 	dup_anon_vma_name(orig, new);
 
+	/* track_pfn_copy() will later take care of copying internal state. */
+	if (unlikely(new->vm_flags & VM_PFNMAP))
+		untrack_pfn_clear(new);
+
 	return new;
 }
 
diff --git a/mm/memory.c b/mm/memory.c
index 3ccee51adfbb..f7fbf099e8f9 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1372,11 +1372,7 @@ copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma)
 		return copy_hugetlb_page_range(dst_mm, src_mm, dst_vma, src_vma);
 
 	if (unlikely(src_vma->vm_flags & VM_PFNMAP)) {
-		/*
-		 * We do not free on error cases below as remove_vma
-		 * gets called on error from higher level routine
-		 */
-		ret = track_pfn_copy(src_vma);
+		ret = track_pfn_copy(dst_vma, src_vma);
 		if (ret)
 			return ret;
 	}
@@ -1413,7 +1409,6 @@ copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma)
 			continue;
 		if (unlikely(copy_p4d_range(dst_vma, src_vma, dst_pgd, src_pgd,
 					    addr, next))) {
-			untrack_pfn_clear(dst_vma);
 			ret = -ENOMEM;
 			break;
 		}
@@ -1423,6 +1418,8 @@ copy_page_range(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma)
 		raw_write_seqcount_end(&src_mm->write_protect_seq);
 		mmu_notifier_invalidate_range_end(&range);
 	}
+	if (ret && unlikely(src_vma->vm_flags & VM_PFNMAP))
+		untrack_pfn_copy(dst_vma, src_vma);
 	return ret;
 }
 
