netdev - Tracking errors in netdevice (and other?) notifiers

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

Date:	Tue, 11 Nov 2014 18:39:29 +0100
From:	Rafał Miłecki <zajec5@...il.com>
To:	Network Development <netdev@...r.kernel.org>
Subject: Tracking errors in netdevice (and other?) notifiers

Hi,

During development of wireless driver I got this poor meaning error:
# ifconfig wlan0_1 up
ifconfig: SIOCSIFFLAGS: Device or resource busy

I've quickly tracked it down to the __dev_open [0]. Then it became worse.
In my case call_netdevice_notifiers returned 32785 which was
translated by notifier_to_errno to the -16 (-EBUSY).

Unfortunately I couldn't track call_netdevice_notifiers. It iterates
over a chain (list) of nameless notifiers (struct notifier_block). I
didn't have a chance to e.g. print a name of notifier that returned an
error.

Is there some trick to do that? To track notifiers and find a code
responsible for the chain error?

In my case it wasn't too hard, because there are only few places in
the kernel registering for NETDEV_PRE_UP. So I checked all of them and
found the guilty one. But I still would like to know if there is some
smart way.

[0] http://lxr.free-electrons.com/source/net/core/dev.c?v=3.17#L1268

-- 
Rafał
--
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