From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933758AbcKGTID (ORCPT ); Mon, 7 Nov 2016 14:08:03 -0500 Received: from gum.cmpxchg.org ([85.214.110.215]:46560 "EHLO gum.cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932876AbcKGTIB (ORCPT ); Mon, 7 Nov 2016 14:08:01 -0500 From: Johannes Weiner To: Andrew Morton Cc: Linus Torvalds , Jan Kara , "Kirill A. Shutemov" , linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@fb.com Subject: [PATCH 1/6] mm: khugepaged: fix radix tree node leak in shmem collapse error path Date: Mon, 7 Nov 2016 14:07:36 -0500 Message-Id: <20161107190741.3619-2-hannes@cmpxchg.org> X-Mailer: git-send-email 2.10.1 In-Reply-To: <20161107190741.3619-1-hannes@cmpxchg.org> References: <20161107190741.3619-1-hannes@cmpxchg.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The radix tree counts valid entries in each tree node. Entries stored in the tree cannot be removed by simpling storing NULL in the slot or the internal counters will be off and the node never gets freed again. When collapsing a shmem page fails, restore the holes that were filled with radix_tree_insert() with a proper radix tree deletion. Fixes: f3f0e1d2150b ("khugepaged: add support of collapse for tmpfs/shmem pages") Reported-by: Jan Kara Signed-off-by: Johannes Weiner --- mm/khugepaged.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 728d7790dc2d..eac6f0580e26 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1520,7 +1520,8 @@ static void collapse_shmem(struct mm_struct *mm, if (!nr_none) break; /* Put holes back where they were */ - radix_tree_replace_slot(slot, NULL); + radix_tree_delete(&mapping->page_tree, + iter.index); nr_none--; continue; } -- 2.10.1