[PATCH] mm/hugetl.c: keep the page mapping info when free_huge_page() hit the VM_BUG_ON_PAGE

From: Yongkai Wu <nic.wuyk@gmail.com>
To: mike.kravetz@oracle.com
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: [PATCH] mm/hugetl.c: keep the page mapping info when free_huge_page() hit the VM_BUG_ON_PAGE
Date: Tue, 13 Nov 2018 20:38:16 +0800	[thread overview]
Message-ID: <CAJtqMcZp5AVva2yOM4gJET8Gd_j_BGJDLTkcqRdJynVCiRRFxQ@mail.gmail.com> (raw)

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It is better to keep page mapping info when free_huge_page() hit the
VM_BUG_ON_PAGE,
so we can get more infomation from the coredump for further analysis.

Signed-off-by: Yongkai Wu <nic_w@163.com>
---
 mm/hugetlb.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index c007fb5..ba693bb 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -1248,10 +1248,11 @@ void free_huge_page(struct page *page)
  (struct hugepage_subpool *)page_private(page);
  bool restore_reserve;

+        VM_BUG_ON_PAGE(page_count(page), page);
+        VM_BUG_ON_PAGE(page_mapcount(page), page);
+
  set_page_private(page, 0);
  page->mapping = NULL;
- VM_BUG_ON_PAGE(page_count(page), page);
- VM_BUG_ON_PAGE(page_mapcount(page), page);
  restore_reserve = PagePrivate(page);
  ClearPagePrivate(page);

-- 
1.8.3.1

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