From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752031AbcBEDlB (ORCPT ); Thu, 4 Feb 2016 22:41:01 -0500 Received: from mga04.intel.com ([192.55.52.120]:27204 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750856AbcBEDk4 (ORCPT ); Thu, 4 Feb 2016 22:40:56 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.22,398,1449561600"; d="scan'208";a="908947958" From: Matthew Wilcox To: Konstantin Khlebnikov , Andrew Morton Cc: Matthew Wilcox , Hugh Dickins , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org Subject: [PATCH 2/2] radix-tree: fix oops after radix_tree_iter_retry Date: Thu, 4 Feb 2016 22:40:48 -0500 Message-Id: <1454643648-10002-3-git-send-email-matthew.r.wilcox@intel.com> X-Mailer: git-send-email 2.7.0.rc3 In-Reply-To: <1454643648-10002-1-git-send-email-matthew.r.wilcox@intel.com> References: <1454643648-10002-1-git-send-email-matthew.r.wilcox@intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org After calling radix_tree_iter_retry(), 'slot' will be set to NULL. This can cause radix_tree_next_slot() to dereference the NULL pointer. Check for a NULL pointer on entry to radix_tree_next_slot(). Reported-by: Konstantin Khlebnikov Signed-off-by: Matthew Wilcox --- include/linux/radix-tree.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 3e488e2..9aa3afe 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -447,6 +447,9 @@ radix_tree_chunk_size(struct radix_tree_iter *iter) static __always_inline void ** radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags) { + if (!slot) + return NULL; + if (flags & RADIX_TREE_ITER_TAGGED) { iter->tags >>= 1; if (likely(iter->tags & 1ul)) { -- 2.7.0.rc3