# Re: \[PATCH\] netlink: Fix netlink\_recvmsg() handling of error from netlink\_dump().

- From: David Miller \<davem@davemloft.net\>
- Date: 2014-07-08 02:37:36 
- List: netdev
- Page: https://ratatoskr.run/netdev/2014/07/10959816
- Thread: https://ratatoskr.run/netdev/2014/06/10959474/t.md

```text
From: Ben Pfaff <redacted>
Date: Mon, 30 Jun 2014 15:35:04 -0700

> netlink_dump() returns a negative errno value on error.  Until now,
> netlink_recvmsg() directly recorded that negative value in sk->sk_err,
> but that's wrong since sk_err takes positive errno values.  (This manifests
> as userspace receiving a positive return value from the recv() system call,
> falsely indicating success.)
> 
> This bug was introduced in the commit that started checking the
> netlink_dump() return value, commit b44d211 (netlink: handle errors from
> netlink_dump()).
> 
> Multithreaded Netlink dumps are one way to trigger this behavior in
> practice, as described in the commit message for the userspace workaround
> posted here:
>     http://openvswitch.org/pipermail/dev/2014-June/042339.html
> 
> Signed-off-by: Ben Pfaff <redacted>

There's another place, later in this file, doing the same exact thing.

Please respin this patch, fixing that location too.

Thanks.
```