From 0b4d372b78bef8ebbccca2e310973b550f1dc6f2 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Thu, 29 Nov 2012 13:54:34 -0800 Subject: mm: soft offline: split thp at the beginning of soft_offline_page() commit 783657a7dc20e5c0efbc9a09a9dd38e238a723da upstream. When we try to soft-offline a thp tail page, put_page() is called on the tail page unthinkingly and VM_BUG_ON is triggered in put_compound_page(). This patch splits thp before going into the main body of soft-offlining. Signed-off-by: Naoya Horiguchi Cc: Andi Kleen Cc: Tony Luck Cc: Andi Kleen Cc: Wu Fengguang Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/memory-failure.c | 8 ++++++++ 1 file changed, 8 insertions(+) (limited to 'mm') diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 274c3cc5fbc..d86fb205735 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1481,9 +1481,17 @@ int soft_offline_page(struct page *page, int flags) { int ret; unsigned long pfn = page_to_pfn(page); + struct page *hpage = compound_trans_head(page); if (PageHuge(page)) return soft_offline_huge_page(page, flags); + if (PageTransHuge(hpage)) { + if (PageAnon(hpage) && unlikely(split_huge_page(hpage))) { + pr_info("soft offline: %#lx: failed to split THP\n", + pfn); + return -EBUSY; + } + } ret = get_any_page(page, pfn, flags); if (ret < 0) -- cgit v1.2.3-18-g5258