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Subject: Re: next-20180605 - BUG in ipv6_add_addr
To:     valdis.kletnieks@vt.edu, netdev@vger.kernel.org
Cc:     linux-kernel@vger.kernel.org
References: <15599.1528402643@turing-police.cc.vt.edu>
From:   David Ahern <dsahern@gmail.com>
Message-ID: <fe2d6bfd-17a3-8464-175d-3e8714e14827@gmail.com>
Date:   Thu, 7 Jun 2018 16:49:07 -0700
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On 6/7/18 1:17 PM, valdis.kletnieks@vt.edu wrote:
> Hit the following, after which my network connection was pretty much hosed
> 
> This ring any bells? I don't have a reproducer for this, so bisecting is problematic....
> 
> [ 1820.832682] BUG: unable to handle kernel NULL pointer dereference at 0000000000000209
> [ 1820.832728] RIP: 0010:ipv6_add_addr+0x280/0xd10
> [ 1820.832732] Code: 49 8b 1f 0f 84 6a 0a 00 00 48 85 db 0f 84 4e 0a 00 00 48 8b 03 48 8b 53 08 49 89 45 00 49 8b 47 10
> 49 89 55 08 48 85 c0 74 15 <48> 8b 50 08 48 8b 00 49 89 95 b8 01 00 00 49 89 85 b0 01 00 00 4c
> [ 1820.832847] RSP: 0018:ffffaa07c2fd7880 EFLAGS: 00010202
> [ 1820.832853] RAX: 0000000000000201 RBX: ffffaa07c2fd79b0 RCX: 0000000000000000
> [ 1820.832858] RDX: a4cfbfba2cbfa64c RSI: 0000000000000000 RDI: ffffffff8a8e9fa0
> [ 1820.832862] RBP: ffffaa07c2fd7920 R08: 000000000000017a R09: ffffffff8a555300
> [ 1820.832866] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888d18e71c00
> [ 1820.832871] R13: ffff888d0a9b1200 R14: 0000000000000000 R15: ffffaa07c2fd7980
> [ 1820.832876] FS:  00007faa51bdb800(0000) GS:ffff888d1d400000(0000) knlGS:0000000000000000
> [ 1820.832880] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [ 1820.832885] CR2: 0000000000000209 CR3: 000000021e8f8001 CR4: 00000000001606e0
> [ 1820.832888] Call Trace:
> [ 1820.832898]  ? __local_bh_enable_ip+0x119/0x260
> [ 1820.832904]  ? ipv6_create_tempaddr+0x259/0x5a0
> [ 1820.832912]  ? __local_bh_enable_ip+0x139/0x260
> [ 1820.832921]  ipv6_create_tempaddr+0x2da/0x5a0
> [ 1820.832926]  ? ipv6_create_tempaddr+0x2da/0x5a0
> [ 1820.832941]  manage_tempaddrs+0x1a5/0x240
> [ 1820.832951]  inet6_addr_del+0x20b/0x3b0
> [ 1820.832959]  ? nla_parse+0xce/0x1e0
> [ 1820.832968]  inet6_rtm_deladdr+0xd9/0x210
> [ 1820.832981]  rtnetlink_rcv_msg+0x1d4/0x5f0

I am the most likely guilty party. I have been staring at the code for
this stack trace for a while and nothing jumps out. Can you send me the
kernel config?