Subject: Re: [BUG -next] sysfs change breaks userspace

From: Tejun Heo <[email-masked]>
Date: Thu, 31 Oct 2013 13:25:06 -0400

Hello, Heiko.

On Thu, Oct 31, 2013 at 12:43:58PM +0100, Heiko Carstens wrote:
> Hi Tejun,
> 
> I just tried out linux-next and my network doesn't come up anymore.
> Userspace fails like this:
> 
> network[2211]: Bringing up interface eth0:  sysfs read broadcast value: Invalid argument
> 
> I bisected that down to:
> 
> commit 13c589d5b0ac654d9da7e490a2dd548e6b86b4a5
> Author: Tejun Heo <[email-masked]>
> Date:   Tue Oct 1 17:42:02 2013 -0400
> 
>     sysfs: use seq_file when reading regular files

Heh, intereting.  The content doesn't change over multiple show
invocations, so the behavior shouldn't change at all for the attribute
and seq_file handles seeking and partial reads correctly.  No idea
what could go wrong there.  It probably was reading
/sys/devices/BLAHBLAH/net/NETIF/broadcast file.  Can you please locate
the file and do "ls -l" and "cat" on it?  If that looks normal, can
you please strace the network interface config program / script /
whatever?  BTW, what are you running on the system?

Thanks.

-- 
tejun