Linux 4.20-rc3 Kernel Released

[phoronix]

Phoronix: Linux 4.20-rc3 Kernel Released

Linus Torvalds just announced the release of Linux 4.20-rc3 as his weekly test release update to the in-development Linux 4.20...

http://www.phoronix.com/scan.php?page=news_item&px=Linux-4.20-rc3-Released

[linner]

Hopefully 4.20 is more stable than 4.19 because I had a hell of a time with systems failing all over until I reverted everything back to 4.18.

[muncrief]

Hopefully 4.20 is more stable than 4.19 because I had a hell of a time with systems failing all over until I reverted everything back to 4.18.

Yes, my system crashes so quickly that no logs are created at all. There's nothing in journalctl, and not even an Xorg log. I have a Sapphire Nitro R9 390 and there's something wrong with amdgpu in the 4.19.x kernel. It boots fine if I don't set amdgpu.cik_support=1, but then I can't use Vulkan. I've tried everything but once I enable amdgpu the system just locks up immediately at boot.

I backed up my system and did a clean test install just in case it was something in my setup but it acted the same way on the new install.

I'm compiling the 4.20-rc3 kernel right now, and I'm hoping it's fixed. I've never had a kernel that crashed without creating any logs before, so I really don't know what else to do.

[wizard69]

The 19 Fedora kernel works for me. Not sure what the Fedora people have done to it, but this is on a Ryzen Mobile platform.

[cRaZy-bisCuiT]

Linux "four twenty" release candidate 3.

[CochainComplex]

I also had some issues with amdgpu and 4.19.1 and 4.19.2 on Raven Ridge (AMD Athlon 200ge) but 4.20-rc2 seems to work - at least for me.
With 4.19.x (debian stretch, buster and even sid / of course latest stable /beta bios) i had blackscreens even with nomodset or other tweaks amdgpu.cik_support=0 amdgpu.dpm=1 amdgpu.dc=1 ...etc. (not sure if this is the reason but the new 18.40 firmware blobs were put upstream after 4.19 was officially released).

How ever 4.20-rc2 is working fine for me - now I hope that STIBP mitigations are not set on by default for raven ridge or at least the performance penalty is not so high.

Does anyone of you know the Kernel Parameter to turn of this mitigations to be on the save side?

Could only find the flags for spectrev1, spectrev2...etc. As far as I know AMD officially recommends not to use STIBP for their Zen based CPUs.

[CochainComplex]

You can remove Spectre stuff with the kernel configuration, make xconfig is your friend. Use the latest AMD wip kernel, as you see it is lottery if mainline kernels works. How to make Debian kernel packages, see: https://www.youtube.com/watch?v=G3AxgH2bbsE

Thx debianxfce - buiding it remotely on a nas. so make menuconfig is my friend. how is the CONFIG_xxx Line called for STIBP ? for one of the spectre eg I can set CONFIG_PAGE_TABLE_ISOLATION=n etc. But somehow I can not find the STIBP settings...maybe I'm blind. Its like opening the fridge and not beeing able to find the butter

Will try the wip kernel soon.

[V10lator]

I've never had a kernel that crashed without creating any logs before

Every software has bugs. Example: On one oft my SBCs every kernel below 4.19 freezes the network at random points in time. Even more funny: In the same SBC the file system (f2fs) freezes without a single log line with kernel 4.14 to 4.19 ... Kernels below 4.14 won't even boot the thing... So while your experience is different I can't use anything other than 4.20-rcX.

[muncrief]

Use the latest AMD wip kernel. Mainline kernels have very few patches and it is lottery when it works. Use the 300Hz kernel timer and xscreensaver.https://cgit.freedesktop.org/~agd5f/linux/

Thank you for the suggestion. I just got done compiling and testing the wip kernel and unfortunately it failed in the same way. I was hoping there might at least be some kind of log generated, but I can't find any.

Does anyone know where else I might be able to look for any kind of log? I can't believe nothing would be generated at all, and expect it's because I'm not looking in the right place. But there's nothing in journalctl, and I can't find anything in /var/log, not even an Xorg log. It's as if the boot attempt was never made at all.

[muncrief]

Every software has bugs. Example: On one oft my SBCs every kernel below 4.19 freezes the network at random points in time. Even more funny: In the same SBC the file system (f2fs) freezes without a single log line with kernel 4.14 to 4.19 ... Kernels below 4.14 won't even boot the thing... So while your experience is different I can't use anything other than 4.20-rcX.

Oh yes, I'm an embedded systems designer that started in the late 80s, so I'm certainly familiar with bugs and freezes. Though none of them were ever my fault!

In any case, I tried the 4.20-rc3 kernel last night and unfortunately it failed in the same way.

So now I'm on a quest for logs and hope someone can let me know where else to look. I'm sure something is being generated and I just don't where it is. As I said before though there's nothing in journalctl, and I can't find anything in /var/log, not even an Xorg log. It's as if the boot attempt was never made at all.