From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg1-f197.google.com (mail-pg1-f197.google.com [209.85.215.197]) by kanga.kvack.org (Postfix) with ESMTP id AB1006B52FB for ; Thu, 30 Aug 2018 16:05:48 -0400 (EDT) Received: by mail-pg1-f197.google.com with SMTP id d132-v6so5527483pgc.22 for ; Thu, 30 Aug 2018 13:05:48 -0700 (PDT) Received: from mga07.intel.com (mga07.intel.com. [134.134.136.100]) by mx.google.com with ESMTPS id x6-v6si7260782pge.100.2018.08.30.13.05.47 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 30 Aug 2018 13:05:47 -0700 (PDT) Subject: [PATCH] mm: fix BUG_ON() in vmf_insert_pfn_pud() from VM_MIXEDMAP removal From: Dave Jiang Date: Thu, 30 Aug 2018 13:05:46 -0700 Message-ID: <153565954666.35458.15832314745699968487.stgit@djiang5-desk3.ch.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-nvdimm@lists.01.org, dan.j.williams@intel.com.vishal.l.verma, ""@intel.com, jack@suse.com 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 Signed-off-by: Dave Jiang --- 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;