Re: rtadvctl -vv show : Segmentation fault

Zhenlei Huang <[email protected]> Wed, 12 Feb 2025 22:33:27 +0800

Newsgroups	gmane.os.freebsd.devel.net,gmane.os.freebsd.current
Message-ID	<[email protected]>


> On Feb 12, 2025, at 10:13 PM, Zhenlei Huang <[email protected]> wrote:
> 
> 
> 
>> On Feb 12, 2025, at 5:42 AM, A FreeBSD User <[email protected]> wrote:
>> 
>> Hello,
>> 
>> I'm running a small 14-STABLE (FreeBSD 14.2-STABLE #11 n270324-8d5d7e2ba3a6: Thu Feb  6
>> 16:56:03 CET 2025 amd64) based router appliance, running rtadvd(8).
>> 
>> When stoppimg/starting mpd5 several times, changing the IPv6 prefix, I can almost with a 100%
>> certainty reproduce such an error calling rtadvctl:
>> 
>> [...]
>> root@gate:~ # rtadvctl -vv show
>> igb0: flags=<UP,CONFIGURED,PERSIST> status=<RA_SEND> mtu 1500
>>       DefaultLifetime: 30m
>>       MinAdvInterval/MaxAdvInterval: 3m20s/10m
>>       AdvLinkMTU: <none>, Flags: <none>, Preference: medium
>>       ReachableTime: 0s, RetransTimer: 0s, CurHopLimit: 64
>>       AdvIfPrefixes: no
>>       Next RA send: Tue Feb 11 22:36:21 2025
>>       Last RA send: Tue Feb 11 22:30:23 2025
>>       Prefixes (1):
>> Segmentation fault
>> [...]
>> 
>> The indication of such a rtadvd failure within our network is no prefix delegation any
>> more, several IPv6 on the (client) hosts's NICs are marked "deprecated" or "detached", but
>> none usable.
>> 
>> Checking on the gateway with the command shown above results in a segmentation fault ... funny.
> 
> Do you get the core dump ? You can attach the core to gdb or lldb to easily figure out which
> line of source code is to be blamed.

The developer's handbook has detailed instructions [1] about how to debug.

[1] https://docs.freebsd.org/en/books/developers-handbook/tools/#debugging

> 
>> 
>> To solve this, we have to restart rtadvd.
>> 
>> --
>> 
>> A FreeBSD user

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