Boot hangs at "loading initial ramdisk..."

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I built a 4.15.0-35 test kernel.

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1792100

Can you test this kernel and see if it resolves this bug?

Note about installing test kernels:
• If the test kernel is prior to 4.15(Bionic) you need to install the linux-image and linux-image-extra .deb packages.
• If the test kernel is 4.15(Bionic) or newer, you need to install the linux-modules, linux-modules-extra and linux-image-unsigned .deb packages.

Thanks in advance!

I get error messages when installing linux-headers:

-- kms@winters:~/Downloads/ubuntu/kernels
=> sudo dpkg -i linux-image-unsigned-4.15.0-35-generic_4.15.0-35.39~lp1792100_amd64.deb linux-modules-* linux-headers-4.15.0-35*
(Reading database ... 599557 files and directories currently installed.)
.
. snip
.
Setting up linux-headers-4.15.0-35-generic (4.15.0-35.39~lp1792100) ...
/etc/kernel/header_postinst.d/dkms:
ERROR (dkms apport): kernel package linux-headers-4.15.0-35-generic is not supported
Error! Bad return status for module build on kernel: 4.15.0-35-generic (x86_64)
Consult /var/lib/dkms/amdgpu/18.20-621984/build/make.log for more information.
Setting up linux-image-unsigned-4.15.0-35-generic (4.15.0-35.39~lp1792100) ...
Setting up linux-modules-extra-4.15.0-35-generic (4.15.0-35.39~lp1792100) ...
Processing triggers for linux-image-unsigned-4.15.0-35-generic (4.15.0-35.39~lp1792100) ...
/etc/kernel/postinst.d/dkms:
ERROR (dkms apport): kernel package linux-headers-4.15.0-35-generic is not supported
Error! Bad return status for module build on kernel: 4.15.0-35-generic (x86_64)
Consult /var/lib/dkms/amdgpu/18.20-621984/build/make.log for more information.
.
. snip
.

The linux-headers package shouldn't be needed to test for this bug. You should only need to install the linux-modules, linux-modules-extra and linux-image-unsigned .deb packages.

The 4.15.0-35 test kernel also hangs at "loading initial ramdisk...".

I started a kernel bisect between Ubuntu-4.15.--32 and Ubuntu-4.15.0-33. The kernel bisect will require testing of about 7-10 test kernels.

I built the first test kernel, up to the following commit:
77a24c313d21e3765b04d90521e9228a9bb6e332

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1792100

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

I'll test this tomorrow.

The kernel 4.15.0-32-generic #35~lp1792100Commit77a24c313d2 works.

I installed an older kernel to use in case of problems. It turns out the some of the older kernels hang in the same way. Here's the rundown on the kernels from the repository:

4.15.0-30: hangs
4.15.0-29: hangs
4.15.0-24: works
4.15.0-20: works

I built the next test kernel, up to the following commit:
7f36a83df6d4fabe39ba597a4eef5ca1f5bbda99

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1792100

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

The 4.15.0-33-generic #37~lp1792100Commit7f36a83df6d kernel works.

I built the next test kernel, up to the following commit:
9627b5742a8e8d87f62d29a8ee04ae867ecd3768

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1792100

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

The 4.15.0-33-generic #37~lp1792100Commit9627b5742a8e kernel works.

I built the next test kernel, up to the following commit:
00c3aa70c712c5f7758370e0cd719ac5e401305e

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1792100

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

The directory http://kernel.ubuntu.com/~jsalisbury/lp1792100 is empty!

Sorry, my upload failed. The .debs are there now.

The 4.15.0-33-generic #37~lp1792100Commit00c3aa70c71 kernel works.

I built the next test kernel, up to the following commit:
84d28cc43f2d9820bd97e8dc428b00483322f660

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1792100

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

The 4.15.0-33-generic #37~lp1792100Commit84d28cc43f2 kernel works.

I built the next test kernel, up to the following commit:
d4be7ce8e6324691737b45f336d770245ba07310

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1792100

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

The 4.15.0-33-generic #37~lp1792100Commitd4be7ce8e632 kernel works.

I built the next test kernel, up to the following commit:
d86a0bd64457a4373623713e93fe8848a9e75ce7

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1792100

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

The 4.15.0-33-generic #37~lp1792100Commitd86a0bd644 kernel works.

I built the next test kernel, up to the following commit:
f03220fb0122a5aced32a57bcb14dde045fc462c

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1792100

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

The 4.15.0-33-generic #37~lp1792100Commitf03220fb0122 kernel works.

I built the next test kernel, up to the following commit:
3dfa1c904fcf138e64658c03f054ef102f52c6ec

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1792100

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

The 4.15.0-33-generic #37~lp1792100Commit3dfa1c904fcf138 kernel works.

I built the next test kernel, up to the following commit:
19e56be2af5ad5333a32da9595f60ec5045d1ca4

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1792100

Can you test that kernel and report back if it has the bug or not? I will build the next test kernel based on your test results.

Thanks in advance

The kernel is missing at http://kernel.ubuntu.com/~jsalisbury/lp1792100.

Sorry about that. The .debs are there now.

The 4.15.0-33-generic #37~lp1792100Commit19e56be2af5a kernel works.

I built a test kernel using the master-next repo.

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1792100

Can you test that kernel and report back if it has the bug or not?

The 4.15.0-39-generic_4.15.0-39.43~lp1792100MasterNext kernel HANGS.

Does it hang at the same point as prior kernels, or does it seem different?

It looks (superficially) the same...
   the purple screen says "loading initial ramdisk..." indefinitely.

If you give me instructions, I could look into it further.

What's interesting is the test kernel in comment #28 was tested as good. That was built with commit 19e56be2af5 as the tip of the tree. That commit is only one commit behind 22df1539aed9, which is the version tag. However, the bug exists when commit 22df1539aed9 is the tip.

I built a v2 version of 4.15.0-33.

The test kernel can be downloaded from:
http://kernel.ubuntu.com/~jsalisbury/lp1792100

Can you test that kernel and report back if it has the bug or not?

The 4.15.0-33-generic #37~lp1792100v2 kernel works.

That was using a stock 4.15.0-33.36 tree that I built. Can you test the official build from the ppa, which is available here:

https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+build/15263551

Just be sure to install all three of the required packages:
 linux-modules, linux-modules-extra and linux-image-unsigned .deb packages.

The 4.15.0-33-generic #36-Ubuntu kernel works.

That is good news, that might indicate this bug is now fixed. Can you apply all the latest updates and the latest kernel to see if the bug still exists?

Neither the 4.18.0-10 nor the 4.15.0-39 kernel will boot.

Hmm, OK, thanks for the feedback. Let me review the bisect results and see if we went astray at some point.

Would it be possible for you to test the latest upstream kernel? Refer to https://wiki.ubuntu.com/KernelMainlineBuilds . Please test the latest v4.20 kernel[0].

[0] http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.20-rc3

The 4.20.0-042000rc3-generic kernel works.

If that is the case, we are better off performing a "Reverse" bisect to identify the fix in mainline versus investigating what went wrong in the first regular bisect.

The steps for a reverse bisect are similar, but we first need to find the last "Bad" kernel and the first "Good" kernel. Can you test the following kernels:

v4.19: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.19/
v4.20-rc1: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.20-rc1

Those kernels are OK.

Can you test 4.18 final:
http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.18/

The 4.18.0-041800-generic kernel works.

Can you test the following kernel? It appears this bug may have been introduced by a SAUCE patch:
-34:

https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+build/15307305

Also, just to confirm to test this kernel you need to install the linux-modules, linux-modules-extra and linux-image-unsigned .deb packages in that order.

Can you also test the following mainline kernels to confirm if this is due to a SAUCE patch or not:

4.15.18: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.15.18/
4.16 Final: http://kernel.ubuntu.com/~kernel-ppa/mainline/v4.16/

The 4.15.0-34-generic downloaded from https://launchpad.net/~canonical-kernel-team/+archive/ubuntu/ppa/+build/15307305 works.

The 4.15.18-041518-generic kernel works.

The 4.16.0-041600-generic kernel works.

Upgrading to 18.10 works.