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From: Adrian Chadd <adrian@freebsd.org>
To: Edgar Martinez <emartinez@kbcnetworks.com>
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Subject: Re: LOR - COM LOCK
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On 11 October 2011 23:49, Edgar Martinez <emartinez@kbcnetworks.com> wrote:
> lock order reversal:
> =A01st 0xc5912778 ath1_scan_lock (ath1_scan_lock) @ /usr/src/sys/net80211=
/ieee80211_node.c:2158
> =A02nd 0xc5911014 ath1_com_lock (ath1_com_lock) @ /usr/src/sys/net80211/i=
eee80211_node.c:2510

This is a bit odd. I'm seeing the same LOR.

>From what I've determined:

* hostap_newstate: the comlock is held, then it calls
ieee80211_iterate_nodes(), which grabs the scan/node lock.
* ioctl -> ieee80211_ioctl -> ieee80211_iterate_nodes() which grabs
the scan/node lock, -> ieee80211_node_leave(), which grabs the
comlock.

I'm not sure what the correct fix should be and I don't have the time
at the moment to fix it. But yes, it should be fixed.


Adrian