Larry,
> You got it right. I got two tracebacks as follows:
>
> [ 22.147978] cfg80211: wiphy->regd changed at line 1459: old (null), new: ffff8800b1e25a80
> [ 22.147982] Pid: 292, comm: kworker/1:1 Not tainted 3.8.0-rc6-wl+ #96
> [ 22.147985] Call Trace:
> [ 22.148032] [<ffffffffa03c6623>] reg_todo+0x403/0x5e0 [cfg80211]
> [ 22.148088] [<ffffffff81063cdd>] process_one_work+0x19d/0x6f0
> [ 22.161223] cfg80211: request_wiphy->regd changed at line 2199: old ffff8800b1e25a80, new: ffff8800b61c66c0
> [ 22.161230] Pid: 2377, comm: crda Not tainted 3.8.0-rc6-wl+ #96
> [ 22.161233] Call Trace:
> [ 22.161275] [<ffffffffa03c76fc>] set_regdom+0x6dc/0x750 [cfg80211]
> [ 22.161293] [<ffffffffa03d1f56>] nl80211_set_reg+0x236/0x2a0 [cfg80211]
> The second one replaced a non-NULL pointer, and kmemleak confirms that it is the
> leaked block.
Ok, good. I'm not sure how a recent change would have caused this
though, but I'm sure we can fix it :)
> This leak seems to occur because I am loading cfg80211 with the regdom set to
> "US"; however, the driver is forcing "CN". That is my penalty for buying the
> adapter on Ebay; however, I think my setting should override that of the driver,
> which might be a separate bug. I'm OK as long as there are no FCC inspectors in
> my neighborhood to see that I am sending out probes on channels 12 and 13.
:)
That might indeed be a different bug.
> I am only vaguely familiar with the rcu routines. Is it sufficient to do the
> simple kfree() before the rcu_assign_pointer() call, or is it necessary to make
> an rcu_lock() call as well? If a simple kfree() is all that is needed, then the
> following patch should be OK. If is is, I'll do some testing and do a proper
> submission later:
No, neither is quite right, another thread might be accessing it at the
same time.
> Index: wireless-testing-new/net/wireless/reg.c
> ===================================================================
> --- wireless-testing-new.orig/net/wireless/reg.c
> +++ wireless-testing-new/net/wireless/reg.c
> @@ -2189,10 +2189,12 @@ static int __set_regdom(const struct iee
> * However if a driver requested this specific regulatory
> * domain we keep it for its private use
> */
> - if (lr->initiator == NL80211_REGDOM_SET_BY_DRIVER)
> + if (lr->initiator == NL80211_REGDOM_SET_BY_DRIVER) {
> + kfree(request_wiphy->regd);
This one should be rcu_free_regdom(), except you also need a temporary
variable:
tmp = get_wiphy_regdom(request_wiphy);
rcu_assign_pointer(request_wiphy->regd, rd);
rcu_free_regdom(tmp);
Note this also works if "tmp" ends up NULL.
johannes
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