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From: Ashutosh Grewal <ashutoshgrewal@gmail.com>
To: davem@davemloft.net, netdev@vger.kernel.org
Subject: Bug: ip utility fails to show routes with large # of multipath next-hops
Date: Tue, 28 Jul 2020 17:52:44 -0700	[thread overview]
Message-ID: <CAKA6ep+EFNOYY8k8PFP9kf_F5GY+5g8qu_LphEAX6N7iEFTs9Q@mail.gmail.com> (raw)

Hello David and all,

I hope this is the correct way to report a bug.

I observed this problem with 256 v4 next-hops or 128 v6 next-hops (or
128 or so # of v4 next-hops with labels).

Here is an example -

root@a6be8c892bb7:/# ip route show 2.2.2.2
Error: Buffer too small for object.
Dump terminated

Kernel details (though I recall running into the same problem on 4.4*
kernel as well) -
root@ubuntu-vm:/# uname -a
Linux ch1 5.4.0-33-generic #37-Ubuntu SMP Thu May 21 12:53:59 UTC 2020
x86_64 x86_64 x86_64 GNU/Linux

I think the problem may be to do with the size of the skbuf being
allocated as part of servicing the netlink request.

static int netlink_dump(struct sock *sk)
{
  <snip>

                skb = alloc_skb(...)

Thanks,
Ashutosh

             reply	other threads:[~2020-07-29  0:52 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-29  0:52 Ashutosh Grewal [this message]
2020-07-29 11:43 ` Bug: ip utility fails to show routes with large # of multipath next-hops Ido Schimmel
2020-07-29 15:17   ` David Ahern
2020-07-31 22:26     ` Ashutosh Grewal

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