It looks like I missed the PUD path when doing VM_MIXEDMAP removal.
This can be triggered by:
1. Boot with memmap=4G!8G
2. build ndctl with destructive flag on
3. make TESTS=device-dax check

[  +0.000675] kernel BUG at mm/huge_memory.c:824!

Applying the same change that was applied to vmf_insert_pfn_pmd() in the
original patch.

Fixes: e1fb4a08649 ("dax: remove VM_MIXEDMAP for fsdax and device dax")

Reported-by: Vishal Verma <[email protected]>
Signed-off-by: Dave Jiang <[email protected]>
---
 mm/huge_memory.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index c3bc7e9c9a2a..533f9b00147d 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -821,11 +821,11 @@ vm_fault_t vmf_insert_pfn_pud(struct vm_area_struct *vma, 
unsigned long addr,
         * but we need to be consistent with PTEs and architectures that
         * can't support a 'special' bit.
         */
-       BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)));
+       BUG_ON(!(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) &&
+                       !pfn_t_devmap(pfn));
        BUG_ON((vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP)) ==
                                                (VM_PFNMAP|VM_MIXEDMAP));
        BUG_ON((vma->vm_flags & VM_PFNMAP) && is_cow_mapping(vma->vm_flags));
-       BUG_ON(!pfn_t_devmap(pfn));
 
        if (addr < vma->vm_start || addr >= vma->vm_end)
                return VM_FAULT_SIGBUS;

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