From: Dave Jiang Date: Tue, 4 Sep 2018 22:46:16 +0000 (-0700) Subject: mm: fix BUG_ON() in vmf_insert_pfn_pud() from VM_MIXEDMAP removal X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=62ec0d8c4f332dedf19d6fad15ddea639044d5fe;p=linux.git 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 Reported-by: Vishal Verma Tested-by: Vishal Verma Acked-by: Jeff Moyer Reviewed-by: Jan Kara Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/huge_memory.c b/mm/huge_memory.c index c3bc7e9c9a2ac..533f9b00147d2 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;