mm: fix BUG_ON() in vmf_insert_pfn_pud() from VM_MIXEDMAP removal

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.

Link: http://lkml.kernel.org/r/153565957352.35524.1005746906902065126.stgit@djiang5-desk3.ch.intel.com
Fixes: e1fb4a08649 ("dax: remove VM_MIXEDMAP for fsdax and device dax")
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Reported-by: Vishal Verma <vishal.l.verma@intel.com>
Tested-by: Vishal Verma <vishal.l.verma@intel.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index c3bc7e9c9a2acc550ea8aeb68720a8c5a611c610..533f9b00147d267644bcbf98da717329fb07c38f 100644 (file)
--- 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;