linux-kernel - attempt to scan fails (device busy) if essid/ssid was changed recently

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]

Message-Id: <1239062401.4705.23.camel@maxim-laptop>
Date:	Tue, 07 Apr 2009 03:00:01 +0300
From:	Maxim Levitsky <maximlevitsky@...il.com>
To:	linux-wireless <linux-wireless@...r.kernel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>
Subject: attempt to scan fails (device busy) if essid/ssid was changed
 recently

Recently I was trying to reduce time it takes for wireless card to
connect.

I noticed that always first attempt at scan fails when NM asks for scan.
I also noticed that this happens with quite recent kernels (I think
2,6.28) didn't have this behavior.

Looking a bit deeper I discovered that each time NM disconnects from a
networks it sets random ssid/essid to the card (using wireless
extensions)

After that scan fails for some time.

as a NM free example you can run 

iwconfig wlan0 essid dummy
iwlist scan

and this will fail

NM in this case waits for whole 10 seconds.

What do you think about this?

I confirm that on iwl3945 and ath5k, so this isn't driver specific.

Best regards,
	Maxim Levitsky

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/