From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out2-smtp.messagingengine.com ([66.111.4.26]:56073 "EHLO out2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750917AbcBLUpC (ORCPT ); Fri, 12 Feb 2016 15:45:02 -0500 Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailout.nyi.internal (Postfix) with ESMTP id 6984F204A6 for ; Fri, 12 Feb 2016 15:45:02 -0500 (EST) Subject: FAILED: patch "[PATCH] mm: hugetlb: call huge_pte_alloc() only if ptep is null" failed to apply to 3.10-stable tree To: n-horiguchi@ah.jp.nec.com, akpm@linux-foundation.org, dave.hansen@intel.com, hillf.zj@alibaba-inc.com, hughd@google.com, iamjoonsoo.kim@lge.com, mgorman@suse.de, mike.kravetz@oracle.com, rientjes@google.com, stable@vger.kernel.org, torvalds@linux-foundation.org Cc: From: Date: Fri, 12 Feb 2016 12:45:01 -0800 Message-ID: <145530990150170@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: The patch below does not apply to the 3.10-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >>From 0d777df5d8953293be090d9ab5a355db893e8357 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Fri, 11 Dec 2015 13:40:49 -0800 Subject: [PATCH] mm: hugetlb: call huge_pte_alloc() only if ptep is null Currently at the beginning of hugetlb_fault(), we call huge_pte_offset() and check whether the obtained *ptep is a migration/hwpoison entry or not. And if not, then we get to call huge_pte_alloc(). This is racy because the *ptep could turn into migration/hwpoison entry after the huge_pte_offset() check. This race results in BUG_ON in huge_pte_alloc(). We don't have to call huge_pte_alloc() when the huge_pte_offset() returns non-NULL, so let's fix this bug with moving the code into else block. Note that the *ptep could turn into a migration/hwpoison entry after this block, but that's not a problem because we have another !pte_present check later (we never go into hugetlb_no_page() in that case.) Fixes: 290408d4a250 ("hugetlb: hugepage migration core") Signed-off-by: Naoya Horiguchi Acked-by: Hillf Danton Acked-by: David Rientjes Cc: Hugh Dickins Cc: Dave Hansen Cc: Mel Gorman Cc: Joonsoo Kim Cc: Mike Kravetz Cc: [2.6.36+] Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 4fe4340ed9b7..9e3fa71b1e18 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -3696,12 +3696,12 @@ int hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma, } else if (unlikely(is_hugetlb_entry_hwpoisoned(entry))) return VM_FAULT_HWPOISON_LARGE | VM_FAULT_SET_HINDEX(hstate_index(h)); + } else { + ptep = huge_pte_alloc(mm, address, huge_page_size(h)); + if (!ptep) + return VM_FAULT_OOM; } - ptep = huge_pte_alloc(mm, address, huge_page_size(h)); - if (!ptep) - return VM_FAULT_OOM; - mapping = vma->vm_file->f_mapping; idx = vma_hugecache_offset(h, vma, address);