Messages in this thread | | | Date | Mon, 06 Feb 2017 22:35:12 -0500 (EST) | Subject | Re: [RFC] igmp: address pmc kmemleak from on igmpv3_del_delrec() | From | David Miller <> |
| |
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.
| |