netdev - Re: locking requirements when calling dev_set

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

Message-ID: <20080702094140.032efd28@extreme>
Date:	Wed, 2 Jul 2008 09:41:40 -0700
From:	Stephen Hemminger <shemminger@...tta.com>
To:	Eli Cohen <eli@....mellanox.co.il>
Cc:	netdev <netdev@...r.kernel.org>, fubar@...ibm.com,
	ogerlitz@...taire.com, Roland Dreier <rdreier@...co.com>,
	general-list <general@...ts.openfabrics.org>
Subject: Re: locking requirements when calling dev_set_mtu()

On Wed, 2 Jul 2008 11:54:09 +0300
Eli Cohen <eli@....mellanox.co.il> wrote:

> Hi,
> 
> I have the need to change the MTU of IP over IB from the driver code
> and not from the shell. Looking for the right way to do it I came
> across the dev_set_mtu() which seems appropriate as it handles all
> notifications too. However, it is not clear to me whether I have to
> wrap the call to dev_set_mtu() with any locks. Specifically, I was
> referred to a mail thread that suggests that I have to use
> rtnl_lock()/rtnl_unlock():
> http://marc.info/?l=linux-netdev&m=121201324611292&w=2
> 
> With reference to the above URL, I would say that it is possible for
> me to hit to the assertion ASSERT_RTNL() if I don't take rtnl_lock
> prior to calling dev_set_mtu(). However I don't hit it, though I can't
> count on that there will not be a case that any function registered
> for notification would expect to see the lock acquired.
> 

You need to call rtnl_lock() so device drivers get consistent locking.
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html