# [SOLVED] Kernels 4.2.0-r1 and 4.2.1 crash

## cfgauss

I can't seem to get 4.2 kernels to work but 4.1.6 does work. The symptom is that KDE will boot and then crash. The keyboard/mouse will sometimes freeze with no warning and I must hard reboot to 4.1.6. Other times KDE produces windows stating that Konsole has just crashed and then Kwin. When this happens, even though sshd has started correctly I can't ssh to the box to shutdown properly, so I assume that sshd has crashed also.

The two 4.2  kernels have the same .config as 4.1.6 together with the normal additional questions answered during make silentoldconfig.

Any debugging hints will be gratefully received.

[SOLVED] After 3+ hours of uptime, kernel 4.2.5 seems to work with no hardware or software changes on my box. The 4.2 kernel series has magically "fixed itself." Woo-hoo! [/SOLVED]Last edited by cfgauss on Sun Nov 01, 2015 3:52 am; edited 1 time in total

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## EasterParade

Unfortunately I cannot help you. I too have one issue with gentoo-sources 4.2.1, by far not as severe as yours though.

When I run 4.1.4 (for example) it´s fine. My only problem with 4.2.1 is that watching tv is impossible as it´s stuttering/choppy.

The config is the same as in 4.1.4 kernel. I cannot pinpoint the source of the problem but kernel 4.2.1 and obviously 4.2.0

too seem to be the reason.

I apologize for this posting as it does not help anyone. I just wanted to stack the kernel discussion with one more message.

May be some of the devs might be interested in some feed-back.

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## russK

My attempt to use 4.2.1 was a disaster, I fell back to 4.0.5 which has been reliable for me.

Under 4.2.1 my virtualbox machines were crashing and dmesg buffer was filling open loop with crap.

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## cfgauss

I had the same problem with 4.2.3 and have masked that one (along with all other 4.2 kernels in portage).

/var/log/rc.log for 4.2.3 looks normal. Where can I look for hints to solutions to this problem?

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## EasterParade

I can confirm: 4.2.3 is the same disappointment.

edit: I reverted to 4.1.8; works nicely

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## cfgauss

I can confirm that 4.1.9-r1 also works. In summary, 4.1 kernels work and 4.2 kernels do not work for me.

If there are problems with 4.2 kernels, I'm puzzled why others haven't reported them. Perhaps the problem is with my hardware/software configuration and not the 4.2 kernels.

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## BlueFusion

I can confirm that 4.2.3 (hardened) kernel causes issues with Qemu/KVM/Virt-Manager.  When creating a new VM through Virt-Manager on my desktop, it uses 100% of one CPU and there is no output through VMC or Spice.  Booting into 4.1.7 (hardened), everything works fine.

Additionally, on my laptop, creating the same VM through Virt-Manager works with 4.2.3 (hardened), until the guest kernel begins to boot.  At this point, I get a kernel panic and a dump.  Again, it works fine with 4.1.7 (hardened).

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## BlueFusion

Apparently, I was wrong about my laptop.  The guest throws a kernel panic with both 4.1.7 and 4.2.3 when using CPU-passthrugh selected (copy host configuration, I believe the prompt says).  When I change it to Nahalem or Westmere, it works.

The laptop is running: a Haswell core i5-4200U CPU @ 1.60GHz

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