Re: [PATCHv5 iproute2] ip route: ignore ENOENT during save if RT_TABLE_MAIN is being dumped

[Roi Dayan <roid@nvidia.com>]

On 2021-07-07 5:50 PM, patchwork-bot+netdevbpf@kernel.org wrote:
> Hello:
> 
> This patch was applied to iproute2/iproute2.git (refs/heads/main):
> 
> On Wed,  7 Jul 2021 15:22:01 +0300 you wrote:
>> We started to use in-kernel filtering feature which allows to get only
>> needed tables (see iproute_dump_filter()). From the kernel side it's
>> implemented in net/ipv4/fib_frontend.c (inet_dump_fib), net/ipv6/ip6_fib.c
>> (inet6_dump_fib). The problem here is that behaviour of "ip route save"
>> was changed after
>> c7e6371bc ("ip route: Add protocol, table id and device to dump request").
>> If filters are used, then kernel returns ENOENT error if requested table
>> is absent, but in newly created net namespace even RT_TABLE_MAIN table
>> doesn't exist. It is really allocated, for instance, after issuing
>> "ip l set lo up".
>>
>> [...]
> 
> Here is the summary with links:
>    - [PATCHv5,iproute2] ip route: ignore ENOENT during save if RT_TABLE_MAIN is being dumped
>      https://git.kernel.org/pub/scm/network/iproute2/iproute2.git/commit/?id=459ce6e3d792
> 
> You are awesome, thank you!
> --
> Deet-doot-dot, I am a bot.
> https://korg.docs.kernel.org/patchwork/pwbot.html
> 
> 


Hi,

I didn't get a chance to check but after this commit the utility ss
is crashing from libnetlink.c

(gdb) bt
#0  0x0000000000000000 in ?? ()
#1  0x0000000000418980 in rtnl_dump_done (a=0x7fffffffdc00, h=0x449c80) 
at libnetlink.c:734
#2  rtnl_dump_filter_l (rth=rth@entry=0x7fffffffdcf0, 
arg=arg@entry=0x7fffffffdc00) at libnetlink.c:893
#3  0x00000000004197a2 in rtnl_dump_filter_nc 
(rth=rth@entry=0x7fffffffdcf0, filter=filter@entry=0x40cdf0 
<show_one_inet_sock>,
     arg1=arg1@entry=0x7fffffffdca0, nc_flags=nc_flags@entry=0) at 
libnetlink.c:957
#4  0x0000000000406dc7 in inet_show_netlink (dump_fp=dump_fp@entry=0x0, 
protocol=protocol@entry=255, f=0x42e900 <current_filter>) at ss.c:3638
#5  0x0000000000404db3 in raw_show (f=0x42e900 <current_filter>) at 
ss.c:3939


if I revert this commit I can run the ss utility ok.

Thanks,
Roi