netdev - Re: Re: Re: [B.A.T.M.A.N.] [PATCH] net: fix possible deadlocks in rtnl

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [day] [month] [year] [list]

Date:	Mon, 03 Dec 2012 21:50:16 +0100
From:	Sven Eckelmann <sven@...fation.org>
To:	Antonio Quartulli <ordex@...istici.org>
Cc:	Eric Dumazet <eric.dumazet@...il.com>,
	Simon Wunderlich <simon.wunderlich@...03.tu-chemnitz.de>,
	b.a.t.m.a.n@...ts.open-mesh.org, netdev@...r.kernel.org,
	davem@...emloft.net, Simon Wunderlich <siwu@....tu-chemnitz.de>
Subject: Re: Re: Re: [B.A.T.M.A.N.] [PATCH] net: fix possible deadlocks in rtnl_trylock/unlock

On Monday 03 December 2012 21:09:06 Antonio Quartulli wrote:
> But still we have the problem in batman-adv (as Sven pointed out in a
> previous email) that tries to unregister a device in that "critical
> window".
> 
> Exporting __rtnl_unlock() would solve the issue in this case.
> 
> If you think the bridge code should not end up in such situation, what if
> Simon resends the patch with only the __rtnl_unlock() exportation and the
> change in batman-adv?

I personally have big doubts about the removal of the second half of the 
unregister. Doesn't sound like the best idea. This would result in side 
effects... one of them for example would be the possible deadlock scenario 
moved to the other users of rtnl_trylock which don't unregister a device 
inside their critical section.... so either you do it always this way when 
using rtnl_trylock or it will break. I don't want to imagine other problems 
caused by this change.

Kind regards,
	Sven
Download attachment "signature.asc" of type "application/pgp-signature" (837 bytes)