From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752507AbaDVGVl (ORCPT ); Tue, 22 Apr 2014 02:21:41 -0400 Received: from cn.fujitsu.com ([59.151.112.132]:13030 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751738AbaDVGUQ (ORCPT ); Tue, 22 Apr 2014 02:20:16 -0400 X-IronPort-AV: E=Sophos;i="4.97,899,1389715200"; d="scan'208";a="29554480" From: Lai Jiangshan To: CC: Andrew Morton , Tejun Heo , Lai Jiangshan , Jean Delvare , Monam Agarwal , Jeff Layton , Andreas Gruenbacher , Stephen Hemminger Subject: [PATCH 2/7 V3] idr: fix unexpected ID-removal when idr_remove(unallocated_id) Date: Tue, 22 Apr 2014 14:23:24 +0800 Message-ID: <1398147810-26414-3-git-send-email-laijs@cn.fujitsu.com> X-Mailer: git-send-email 1.7.4.4 In-Reply-To: <1398147810-26414-1-git-send-email-laijs@cn.fujitsu.com> References: <20140421152345.4d67a6563ebd89f0b969332f@linux-foundation.org> <1398147810-26414-1-git-send-email-laijs@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.167.226.103] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If unallocated_id = (ANY * idr_max(idp->layers) + existing_id) is passed to idr_remove(). The existing_id will be removed unexpectedly. The following test shows this unexpected id-removal: static void test4(void) { int id; DEFINE_IDR(test_idr); printk(KERN_INFO "Start test4\n"); id = idr_alloc(&test_idr, (void *)1, 42, 43, GFP_KERNEL); BUG_ON(id != 42); idr_remove(&test_idr, 42 + IDR_SIZE); TEST_BUG_ON(idr_find(&test_idr, 42) != (void *)1); idr_destroy(&test_idr); printk(KERN_INFO "End of test4\n"); } ida_remove() shares the similar problem. It happens only when the caller tries to free an unallocated ID which is the caller's fault. It is not a bug. But it is better to add the proper check and complain rather than removing an existing_id silently. Signed-off-by: Lai Jiangshan Acked-by: Tejun Heo --- lib/idr.c | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-) diff --git a/lib/idr.c b/lib/idr.c index 4df6792..c4afd94 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -562,6 +562,11 @@ void idr_remove(struct idr *idp, int id) if (id < 0) return; + if (id > idr_max(idp->layers)) { + idr_remove_warning(id); + return; + } + sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); if (idp->top && idp->top->count == 1 && (idp->layers > 1) && idp->top->ary[0]) { @@ -1025,6 +1030,9 @@ void ida_remove(struct ida *ida, int id) int n; struct ida_bitmap *bitmap; + if (idr_id > idr_max(ida->idr.layers)) + goto err; + /* clear full bits while looking up the leaf idr_layer */ while ((shift > 0) && p) { n = (idr_id >> shift) & IDR_MASK; -- 1.7.4.4