Re: [PATCH 1/1] bridge: mdb: fix leak on complete_info ptr on fail path

[David Miller]

From: Eduardo Valentin <eduval@xxxxxxxxxx>
Date: Tue, 11 Jul 2017 14:55:12 -0700

> We currently get the following kmemleak report:
> unreferenced object 0xffff8800039d9820 (size 32):
>   comm "softirq", pid 0, jiffies 4295212383 (age 792.416s)
>   hex dump (first 32 bytes):
>     00 0c e0 03 00 88 ff ff ff 02 00 00 00 00 00 00  ................
>     00 00 00 01 ff 11 00 02 86 dd 00 00 ff ff ff ff  ................
>   backtrace:
>     [<ffffffff8152b4aa>] kmemleak_alloc+0x4a/0xa0
>     [<ffffffff811d8ec8>] kmem_cache_alloc_trace+0xb8/0x1c0
>     [<ffffffffa0389683>] __br_mdb_notify+0x2a3/0x300 [bridge]
>     [<ffffffffa038a0ce>] br_mdb_notify+0x6e/0x70 [bridge]
>     [<ffffffffa0386479>] br_multicast_add_group+0x109/0x150 [bridge]
>     [<ffffffffa0386518>] br_ip6_multicast_add_group+0x58/0x60 [bridge]
>     [<ffffffffa0387fb5>] br_multicast_rcv+0x1d5/0xdb0 [bridge]
>     [<ffffffffa037d7cf>] br_handle_frame_finish+0xcf/0x510 [bridge]
>     [<ffffffffa03a236b>] br_nf_hook_thresh.part.27+0xb/0x10 [br_netfilter]
>     [<ffffffffa03a3738>] br_nf_hook_thresh+0x48/0xb0 [br_netfilter]
>     [<ffffffffa03a3fb9>] br_nf_pre_routing_finish_ipv6+0x109/0x1d0 [br_netfilter]
>     [<ffffffffa03a4400>] br_nf_pre_routing_ipv6+0xd0/0x14c [br_netfilter]
>     [<ffffffffa03a3c27>] br_nf_pre_routing+0x197/0x3d0 [br_netfilter]
>     [<ffffffff814a2952>] nf_iterate+0x52/0x60
>     [<ffffffff814a29bc>] nf_hook_slow+0x5c/0xb0
>     [<ffffffffa037ddf4>] br_handle_frame+0x1a4/0x2c0 [bridge]
> 
> This happens when switchdev_port_obj_add() fails. This patch
> frees complete_info object in the fail path.

Applied, thanks.

I'm so glad I pushed back on your original patch :-)

> Cc: stable <stable@xxxxxxxxxxxxxxx> # v4.9+

Please do not add stable tags to networking patches, I queue up and
submit networking -stable changes myself upon request which I am doing
in this case as well.

Thanks.