RPi 3 WiFi - kernel NULL pointer dereference #1442
Comments
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This appears to be a very similar crash to the crash with the official USB wifi dongle which I reported last year: #1234 |
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Here is another report of the same crash: guysoft/OctoPi#207 |
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This also looks like the same crash, even though it is completely different hardware: https://bugzilla.kernel.org/show_bug.cgi?id=100201 |
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I've followed those steps on a clean Jessie-Lite installation and I'm not seeing a crash. How is your WiFi network configured? |
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I see the same issue. For me it depends on the WiFi I connect to though. With a Vodafone box, everything was fine. Now I switched to a "o2 HomeBox 6441" and I see crashes. My analysis leads me to believe that the channel for the 2.4GHz network is the culprit. See below. The new box supports 5Ghz 802.11ac/n/a AND 802.11b/g/n which can be turned on and off independently and on different SSIDs. Also the channel can be AUTO or manually set. I played around with the settings and figured the following out: If I let the channel on AUTO for 2.4Ghz, the router chooses 13, this leads to a crash on the raspberry PI. Choosing manually the channel gives these results: CH 12 and 13 crash the RaspberryPi, 11 and everything below are working fine. |
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Thank you, @SirVer, that's useful feedback. |
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For some reason the brcmfmac driver in the 4.1 kernel doesn't support channels 12 and 13, even though the regulations in some regions allow them. I'm in the UK, and on 4.1 I see: but 4.4 shows: Perhaps the crash occurs because the lack of support is as the result of a bug, and in some code paths that leads to a NULL pointer. |
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Channel 13 here too, also with router supporting AC and multiple SSIDs (both are in use). |
Did the kernel freeze in the interval between these two messages? |
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There is no reason to think that there was a freeze. Kernels aren't normally very chatty. The solution to this problem is to upgrade to a 4.4 kernel. All rpi-update kernels are now 4.4-based, and an apt-get 4.4 kernel will be released soon. |
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Thank you @pelwell |
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On 4.4.9+ 884 I still can't connect to channel 12 or 13 APs with brcmfmac devices. |
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What is your regulatory domain set to? What output do you get from |
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I'll get all that info for you tomorrow. Note when I said "I cant connect" I meant that I can't connect because the Pi still crashes. It does connect and get an IP address and set the clock correctly with NTP... then it just dies a couple of minutes later. I'll have to connect up an ethernet cable to see what is going on. |
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It turns out that the access point set to channel 13 also has wireless isolation enabled. It actually works fine now. |
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Does that mean we can close this now? |
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Fixed in 4.4 |
Using 2016-03-18-raspbian-jessie-lite. This is reproducible every single time, within a minute of booting. Then I get about another minute to copy out logs before the whole system freezes.
These files were modified:
/etc/network/interfaces - "wireless-power off" was added:
wpa_supplicant.conf - ssid and psk were added:
No other files in the system were modified.
Full dmesg from boot to crash:
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