ifup wlan0 causes kernel Oops

Question

on my laptop, when I do ifup wlan0, sometimes I get following call trace in dmesg. Other times, the log looks perfectly normal, and there are no kernel Oops messages.

In both cases (with errors and without), my network seems to work fine.

But I would like to understand what is happening. Could somebody please help me interpret the meaning of the call trace messages ?

kernel: [181794.747548] ------------[ cut here ]------------
kernel: [181794.747560] WARNING: CPU: 2 PID: 8430 at net/wireless/reg.c:1806 0xffffffff8147a677()
kernel: [181794.747570] CPU: 2 PID: 8430 Comm: kworker/2:0 Tainted: G        W     3.16.6 #1
kernel: [181794.747574] Hardware name: Dell Inc. Latitude E7440/03HFCG, BIOS A09 05/01/2014
kernel: [181794.747579] Workqueue: events 0xffffffff8147a740
kernel: [181794.747584]  0000000000000000 0000000000000009 ffffffff814c43fb 0000000000000000
kernel: [181794.747592]  ffffffff81058185 0000000000011500 ffffffff8147a677 ffff88040d4cb300
kernel: [181794.747598]  ffff8804082e7e00 0000000000000003 ffff88040d440240 ffff8804082e7e00
kernel: [181794.747605] Call Trace:
kernel: [181794.747611]  [<ffffffff814c43fb>] ? 0xffffffff814c43fb
kernel: [181794.747615]  [<ffffffff81058185>] ? 0xffffffff81058185
kernel: [181794.747619]  [<ffffffff8147a677>] ? 0xffffffff8147a677
kernel: [181794.747623]  [<ffffffff8147a677>] ? 0xffffffff8147a677
kernel: [181794.747627]  [<ffffffff8147a7ae>] ? 0xffffffff8147a7ae
kernel: [181794.747630]  [<ffffffff81067c27>] ? 0xffffffff81067c27
kernel: [181794.747634]  [<ffffffff8106806f>] ? 0xffffffff8106806f
kernel: [181794.747638]  [<ffffffff81067d7d>] ? 0xffffffff81067d7d
kernel: [181794.747642]  [<ffffffff8106cc2d>] ? 0xffffffff8106cc2d
kernel: [181794.747645]  [<ffffffff8106cb68>] ? 0xffffffff8106cb68
kernel: [181794.747649]  [<ffffffff814cb16c>] ? 0xffffffff814cb16c
kernel: [181794.747653]  [<ffffffff8106cb68>] ? 0xffffffff8106cb68
kernel: [181794.747657] ---[ end trace 269bc2d623c15a61 ]---
kernel: [181794.747661] cfg80211: Calling CRDA for country: DE
kernel: [181794.790714] CPU: 2 PID: 8430 Comm: kworker/2:0 Tainted: G        W     3.16.6 #1
kernel: [181794.790717] Hardware name: Dell Inc. Latitude E7440/03HFCG, BIOS A09 05/01/2014
kernel: [181794.790720] Workqueue: events 0xffffffff8147a740
kernel: [181794.790723]  0000000000000000 0000000000000009 ffffffff814c43fb 0000000000000000
kernel: [181794.790728]  ffffffff81058185 0000000000011500 ffffffff8147a677 ffff88040d4cb300
kernel: [181794.790732]  ffff8804082e7e00 0000000000000003 ffff88040d440240 ffff8804082e7e00
kernel: [181794.790736] Call Trace:
kernel: [181794.790740]  [<ffffffff814c43fb>] ? 0xffffffff814c43fb
kernel: [181794.790743]  [<ffffffff81058185>] ? 0xffffffff81058185
kernel: [181794.790745]  [<ffffffff8147a677>] ? 0xffffffff8147a677
kernel: [181794.790747]  [<ffffffff8147a677>] ? 0xffffffff8147a677
kernel: [181794.790750]  [<ffffffff8147a7ae>] ? 0xffffffff8147a7ae
kernel: [181794.790752]  [<ffffffff81067c27>] ? 0xffffffff81067c27
kernel: [181794.790754]  [<ffffffff8106806f>] ? 0xffffffff8106806f
kernel: [181794.790757]  [<ffffffff81067d7d>] ? 0xffffffff81067d7d
kernel: [181794.790759]  [<ffffffff8106cc2d>] ? 0xffffffff8106cc2d
kernel: [181794.790761]  [<ffffffff8106cb68>] ? 0xffffffff8106cb68
kernel: [181794.790763]  [<ffffffff814cb16c>] ? 0xffffffff814cb16c
kernel: [181794.790766]  [<ffffffff8106cb68>] ? 0xffffffff8106cb68
kernel: [181794.790768] ---[ end trace 269bc2d623c15a62 ]---
kernel: [181794.790771] cfg80211: Calling CRDA for country: DE
kernel: [181794.972483] ------------[ cut here ]------------

For completion, I might add that this is a new laptop, but I have replaced the original wifi card (Intel Dualband Wireless-AC 7260) with my own card (Intel Centrino Ultimate-N 6300)

I am using Debian Wheezy with my own kernel 3.16.6

Answer 1

Turns out to be a false warning.

To quote from the (now closed) kernel bug report:

Alfred Krohmer: If I unterstand your patch correctly it just removes the warning, but it won't actually fix the driver crash this bug report was submitted for. So why mark it as resolved?

Emmanuel Grumbach: There is no real bug. The commit message explains this.

Well, I see the same error in dmesg but my Wifi connections works fine. (I'm using a Lenovo Thinkpad W540.) Interestingly, the Arch Linux bug report is still open, and some say that the have connection problems.