Linux – How to determine which module taints the kernel

fedorakernel-moduleskernel-paniclinux-kernel

My kernel keeps panicking when connected to a certain wireless network. I'd like to send a bug report but my kernel is apparently tainted. From /var/log/messages:

Apr 17 21:28:22 Eiger kernel: [13330.442453] Pid: 4095, comm: kworker/u:1 Tainted: G           O 3.8.4-102.fc17.x86_64 #1

and 

[root@Eiger ~]# cat /proc/sys/kernel/tainted 
4096

I've not been able to find documentation for what the 4096 bitmask means, but the G flag means that an external GPL module is loaded into the kernel. How do I find out which module is tainting the kernel?

I've grepped for [Tt]aint in /var/log/messages or dmesg and don't find anything corresponding to when a module is loaded. My kernel is the latest kernel from Fedora 17: 3.8.4-102.fc17.x86_64.

UPDATE: It may be due to the rts5139 module. It shows up in lsmod but modinfo rts5139 produces ERROR: Module rts5139 not found. When booting the previous kernel, 3.8.3-103.fc17.x86_64, this module is not listed by lsmod and the kernel is not tainted (/proc/sys/kernel/taint is 0).

I've tried blacklisting this module

echo 'blacklist rts5139' >> /etc/modprobe.d/blacklist.conf

but rebooting still shows the kernel as tainted.

Best Answer

Well I don't believe a standard Fedora kernel package will include any modules which would trigger this taint so the question is, what other kernel modules have you installed?

Common candidates would be graphics drivers (though I think those will mostly set the "proprietary" bit) and wireless drivers.

If you can find anything in the lsmod output that you think may be a candidate then run modinfo <module-name> and see if the output includes intree: Y as any module without that will trigger the taint you are seeing.

UPDATE: The rts5139 module that you're seeing in lsmod but which doesn't seem to be on your system is probably in the initrd and is being loaded from there early in the boot process before the main filesystem is mounted.

That also explains why blacklisting won't work as you would have to rebuild the initrd with the updated blacklist. Rebuilding the initrd with dracut will cause the module to go away anyway though.

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