From mboxrd@z Thu Jan  1 00:00:00 1970
From: Arun Sharma <asharma@fb.com>
Subject: Re: route add default fails with ESRCH?
Date: Wed, 22 Feb 2012 17:26:26 -0800
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References: <alpine.LFD.2.00.1202222319150.1603@ja.ssi.bg> <4F45638B.30305@fb.com> <4F45742F.1070605@fb.com> <20120222.185625.1452176745900047968.davem@davemloft.net>
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Cc: <ja@ssi.bg>, <netdev@vger.kernel.org>,
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To: David Miller <davem@davemloft.net>
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On 2/22/12 3:56 PM, David Miller wrote:
>
> It breaks because that script sequence quoted above depends upon the
> order in which the routes are listed.  Since fib_hash and fib_trie use
> different datastructures, the order in which route entries are dumped
> will not be the same and this is completely unavoidable.

Here's a minimal repro case:

# ip route flush default
# route add default gw 192.168.143.2
SIOCADDRT: No such process

This fails for me on both 2.6.38 and 3.2.

I think the dependency we have is the actual format of the default route 
entry:

fib_hash:

# ip route
<bunch of routes>
throw default

fib_trie:

# ip route
default via 192.168.143.2 dev eth0  proto static
<bunch of routes>

when the output was piped to awk '{ print $1 }' we ended up deleting the 
default route for fib_trie case, but not the fib_hash case.

I'll just fix up our scripts. Thanks for looking into it.

  -Arun