From: David Miller <davem@davemloft.net>
To: xiyou.wangcong@gmail.com
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
Subject: Re: [RFC] igmp: address pmc kmemleak from on igmpv3_del_delrec()
Date: Mon, 06 Feb 2017 22:35:12 -0500 (EST) [thread overview]
Message-ID: <20170206.223512.698362451560656620.davem@davemloft.net> (raw)
In-Reply-To: <CAM_iQpXDk5SOX3sM32M+DdLG=J0mKZ9JZ9gdVDLkLxVzaSGprA@mail.gmail.com>
From: Cong Wang <xiyou.wangcong@gmail.com>
Date: Mon, 6 Feb 2017 16:32:14 -0800
> On Fri, Feb 3, 2017 at 1:20 PM, Luis R. Rodriguez <mcgrof@kernel.org> 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:
>> [<ffffffffb3a5f7ea>] kmemleak_alloc+0x4a/0xa0
>> [<ffffffffb36044e7>] kmem_cache_alloc_trace+0x107/0x240
>> [<ffffffffb39ddbed>] igmp_group_dropped+0xfd/0x270
>> [<ffffffffb39de5cf>] ip_mc_dec_group+0xaf/0x110
>> [<ffffffffb39de6e6>] ip_mc_leave_group+0xb6/0x140
>> [<ffffffffb39a55d7>] do_ip_setsockopt.isra.13+0x4c7/0xed0
>> [<ffffffffb39a6014>] ip_setsockopt+0x34/0xb0
>> [<ffffffffb39ced9b>] udp_setsockopt+0x1b/0x30
>> [<ffffffffb393f064>] sock_common_setsockopt+0x14/0x20
>> [<ffffffffb393dd10>] SyS_setsockopt+0x80/0xe0
>> [<ffffffffb3403b4b>] do_syscall_64+0x5b/0xc0
>> [<ffffffffb3a6b3af>] return_from_SYSCALL_64+0x0/0x6a
>> [<ffffffffffffffff>] 0xffffffffffffffff
>>
>> Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
>> ---
>>
>> 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 <liuhangbin@gmail.com>
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.
prev parent reply other threads:[~2017-02-07 3:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-03 21:20 [RFC] igmp: address pmc kmemleak from on igmpv3_del_delrec() Luis R. Rodriguez
2017-02-07 0:32 ` Cong Wang
2017-02-07 3:35 ` David Miller [this message]
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