Re: [PATCH] netlink: handle errors from netlink_dump()

[David Miller <davem@davemloft.net>]

From: Andrey Vagin <avagin@openvz.org>
Date: Mon, 21 Feb 2011 15:40:47 +0300

> netlink_dump() may failed, but nobody handle its error.
> It generates output data, when a previous portion has been returned to
> user space. This mechanism works when all data isn't go in skb. If we
> enter in netlink_recvmsg() and skb is absent in the recv queue, the
> netlink_dump() will not been executed. So if netlink_dump() is failed
> one time, the new data never appear and the reader will sleep forever.
> 
> netlink_dump() is called from two places:
> 
> 1. from netlink_sendmsg->...->netlink_dump_start().
>    In this place we can report error directly and it will be returned
>    by sendmsg().
> 
> 2. from netlink_recvmsg
>    There we can't report error directly, because we have a portion of
>    valid output data and call netlink_dump() for prepare the next portion.
>    If netlink_dump() is failed, the socket will be mark as error and the
>    next recvmsg will be failed.
> 
> Signed-off-by: Andrey Vagin <avagin@openvz.org>

This issue has existed since the very creation of the netlink code :-)

Applied, thanks!