From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [RFC] igmp: address pmc kmemleak from on igmpv3_del_delrec() Date: Mon, 06 Feb 2017 22:35:12 -0500 (EST) Message-ID: <20170206.223512.698362451560656620.davem@davemloft.net> References: <20170203212047.31653-1-mcgrof@kernel.org> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: mcgrof@kernel.org, kuznet@ms2.inr.ac.ru, jmorris@namei.org, yoshfuji@linux-ipv6.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, kernel@kyup.com, liuhangbin@gmail.com To: xiyou.wangcong@gmail.com Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org From: Cong Wang Date: Mon, 6 Feb 2017 16:32:14 -0800 > On Fri, Feb 3, 2017 at 1:20 PM, Luis R. Rodriguez wrote: >> When we igmpv3_add_delrec() we kzalloc the pmc, but when users >> call igmpv3_del_delrec() we never free the pmc. This was caught >> by the following kmemleak splat: >> >> unreferenced object 0xffff99666ff43b40 (size 192): >> comm "systemd-resolve", pid 1258, jiffies 4309905600 (age 2138.352s) >> hex dump (first 32 bytes): >> 00 6a 64 72 66 99 ff ff e0 00 00 fc 00 00 00 00 .jdrf........... >> 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ >> backtrace: >> [] kmemleak_alloc+0x4a/0xa0 >> [] kmem_cache_alloc_trace+0x107/0x240 >> [] igmp_group_dropped+0xfd/0x270 >> [] ip_mc_dec_group+0xaf/0x110 >> [] ip_mc_leave_group+0xb6/0x140 >> [] do_ip_setsockopt.isra.13+0x4c7/0xed0 >> [] ip_setsockopt+0x34/0xb0 >> [] udp_setsockopt+0x1b/0x30 >> [] sock_common_setsockopt+0x14/0x20 >> [] SyS_setsockopt+0x80/0xe0 >> [] do_syscall_64+0x5b/0xc0 >> [] return_from_SYSCALL_64+0x0/0x6a >> [] 0xffffffffffffffff >> >> Signed-off-by: Luis R. Rodriguez >> --- >> >> I can reproduce this over time on a qemu box running next-20170125. >> After running this for a while I no longer see the splat. This needs >> confirmation form folks more familiar with the code, hence RFC. If >> this is a real fix we need appropriate tags for the patch. > > > Looks good to me. Adding some people who recent touched it to CC. The kfree() was removed in commit: ==================== commit 24803f38a5c0b6c57ed800b47e695f9ce474bc3a Author: Hangbin Liu Date: Mon Nov 14 16:16:28 2016 +0800 igmp: do not remove igmp souce list info when set link down ==================== But I don't see what could possibly continue to reference this pmc after we unlink it from the list.