From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:34414 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S937081AbdAJNuM (ORCPT ); Tue, 10 Jan 2017 08:50:12 -0500 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Johannes Weiner , Jan Kara , "Kirill A. Shutemov" , Hugh Dickins , Matthew Wilcox , Andrew Morton , Linus Torvalds Subject: [PATCH 4.9 142/206] mm: khugepaged: fix radix tree node leak in shmem collapse error path Date: Tue, 10 Jan 2017 14:37:05 +0100 Message-Id: <20170110131509.297992874@linuxfoundation.org> In-Reply-To: <20170110131502.767555407@linuxfoundation.org> References: <20170110131502.767555407@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: stable-owner@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Johannes Weiner commit 59749e6ce53735d8b696763742225f126e94603f upstream. 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") Link: http://lkml.kernel.org/r/20161117191138.22769-3-hannes@cmpxchg.org Signed-off-by: Johannes Weiner Reported-by: Jan Kara Acked-by: Kirill A. Shutemov Reviewed-by: Jan Kara Cc: Hugh Dickins Cc: Matthew Wilcox Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/khugepaged.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1525,9 +1525,11 @@ tree_unlocked: if (!page || iter.index < page->index) { if (!nr_none) break; - /* Put holes back where they were */ - radix_tree_replace_slot(slot, NULL); nr_none--; + /* Put holes back where they were */ + radix_tree_delete(&mapping->page_tree, + iter.index); + slot = radix_tree_iter_next(&iter); continue; }