kernel panic attempting to boot kernel 4.12-rc3

[Nicholas Stommel]

I have an HP Spectre x360 Convertible laptop with an Intel 5500U SoC. In short, I am completely unable to boot kernel 4.12-rc3, even though I could boot from 4.12-rc2 perfectly fine. The loading screen does not appear at all, instead GRUB remains stuck on "Loading initial ramdisk ...". Please help. I don't know how to identify what is wrong because I am completely unable to boot the OS to begin with. Needless to say, this is a major problem.

Here is my hardware:

H/W path Device Class Description
====================================================
                          system HP Spectre x360 Convertible (N5R94UA)
/0 bus 802D
/0/0 memory 64KiB BIOS
/0/10 memory 32KiB L1 cache
/0/11 memory 32KiB L1 cache
/0/12 memory 256KiB L2 cache
/0/13 memory 4MiB L3 cache
/0/14 processor Intel(R) Core(TM) i7-5500U CPU @ 2.40GH
/0/16 memory 8GiB System Memory
/0/16/0 memory 4GiB Row of chips Synchronous 1600 MHz
/0/16/1 memory 4GiB Row of chips Synchronous 1600 MHz
/0/100 bridge Broadwell-U Host Bridge -OPI
/0/100/2 display Broadwell-U Integrated Graphics
/0/100/3 multimedia Broadwell-U Audio Controller
/0/100/14 bus Wildcat Point-LP USB xHCI Controller
/0/100/14/0 usb1 bus xHCI Host Controller
/0/100/14/0/1 input USB Receiver
/0/100/14/0/3 multimedia HP Truevision Full HD
/0/100/14/0/4 input Touchscreen
/0/100/14/0/5 input ITE Device(8350)
/0/100/14/0/7 communication Bluetooth wireless interface
/0/100/14/1 usb2 bus xHCI Host Controller
/0/100/16 communication Wildcat Point-LP MEI Controller #1
/0/100/1c bridge Wildcat Point-LP PCI Express Root Port
/0/100/1c/0 generic RTS5227 PCI Express Card Reader
/0/100/1c.2 bridge Wildcat Point-LP PCI Express Root Port
/0/100/1c.2/0 wlo1 network Wireless 7265
/0/100/1f bridge Wildcat Point-LP LPC Controller
/0/100/1f.2 storage Wildcat Point-LP SATA Controller [AHCI
/0/100/1f.3 bus Wildcat Point-LP SMBus Controller
/0/1 scsi0 storage
/0/1/0.0.0 /dev/sda disk 512GB SAMSUNG MZNTE512
/0/1/0.0.0/1 /dev/sda1 volume 449MiB Windows NTFS volume
/0/1/0.0.0/2 /dev/sda2 volume 99MiB Windows FAT volume
/0/1/0.0.0/3 /dev/sda3 volume 15MiB reserved partition
/0/1/0.0.0/4 /dev/sda4 volume 15EiB Windows FAT volume
/0/1/0.0.0/5 /dev/sda5 volume 838MiB Windows NTFS volume
/0/1/0.0.0/6 /dev/sda6 volume 146GiB Windows NTFS volume
/0/1/0.0.0/7 /dev/sda7 volume 89GiB EXT4 volume
/0/1/0.0.0/8 /dev/sda8 volume 8099MiB Linux swap volume
/1 power PK03056XL

[Nicholas Stommel (nstommel)]

It appears a kernel panic is happening immediately while attempting to boot 4.12-rc3, it doesn't happen on 4.12-rc2.
Adding earlyprintk=efi to the grub command line options, I get the following message (which explains why the bootloader stops at 'loading initial ramdisk...'):

This was meticulously copied from a photo of a GRUB screen, this change is undoubtedly the culprit: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/diff/arch/x86/mm/pat.c?id=v4.12-rc3&id2=v4.12-rc2
(direct commit at)
https://github.com/torvalds/linux/commit/cbed27cdf0e3f7ea3b2259e86b9e34df02be3fe4

[ 0.000000] Kernel panic - not syncing: x86/PAT: PAT enabled, but not supported by secondary CPU
[ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.12.0-041200rc3-generic #201705282131
[ 0.000000] Hardware name: HP HP Spectre x360 Convertible /802D, BIOS F.45 04/21/2017
[ 0.000000] Call Trace:
[ 0.000000] dump_stack+0x63/0x8d
[ 0.000000] panic+0xe4/0x22d
[ 0.000000] pat_init+0x13d/0x140
[ 0.000000] generic_set_all+0x1ab/0x300
[ 0.000000] mtrr_bp_init+0x1e5/0x227
[ 0.000000] setup_arch+0x53a/0xca8
[ 0.000000] ? printk+0x52/0x6e
[ 0.000000] ? early_idt_handler_array+0x120/0x120
[ 0.000000] start_kernel+0xb7/0x46c
[ 0.000000] ? early_idt_handler_array+0x120/0x120
[ 0.000000] x86_64_start_reservations+0x29/0x2b
[ 0.000000] x86_64_start_kernel+0x154/0x177
[ 0.000000] secondary_startup_64+0x9f/0x9f
[ 0.000000] ---[ end Kernel panic - not syncing: x86/PAT: PAT enabled, but not supported by secondary CPU
[ 0.000000]

This change causes a kernel panic on my Intel 5500U processor, I literally cannot boot my computer. This commit results in a serious regression for multicore Intel CPUs, 4.12-rc3 and drm-tip result in an immediate kernel panic attempting to boot. This is unacceptable.

[Brad Figg (brad-figg)]

This bug is missing log files that will aid in diagnosing the problem. From a terminal window please run:

apport-collect 1694561

and then change the status of the bug to 'Confirmed'.

If, due to the nature of the issue you have encountered, you are unable to run this command, please add a comment stating that fact and change the bug status to 'Confirmed'.

This change has been made by an automated script, maintained by the Ubuntu Kernel Team.

[Nicholas Stommel (nstommel)]

I am unable to run apport-collect running 4.12-rc3, because I cannot actually boot my computer (an immediate kernel panic occurs, as evidenced by adding the output from earlyprintk=efi), so I'm marking this bug as confirmed. Please also see relevant discussion about this issue on the Linux Kernel mailing list: http://lkml.iu.edu/hypermail/linux/kernel/1705.3/04549.html

[Joseph Salisbury (jsalisbury)]

This issue appears to be an upstream bug, since you tested the latest upstream kernel. Would it be possible for you to open an upstream bug report[0]? That will allow the upstream Developers to examine the issue, and may provide a quicker resolution to the bug.

Please follow the instructions on the wiki page[0]. The first step is to email the appropriate mailing list. If no response is received, then a bug may be opened on bugzilla.kernel.org.

Once this bug is reported upstream, please add the tag: 'kernel-bug-reported-upstream'.

[0] https://wiki.ubuntu.com/Bugs/Upstream/kernel

[iLogin (cerebellum-l)]

revert a broken PAT commit that broke a number of systems

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=f2a025defd804be938f8acffe62e4801a3ed1601

[John S. Gruber (jsjgruber)]

@iLogin That does revert the troublesome commit and mainline at that commit boots for me.

[pdecat (pdecat)]

Same issue with Dell XPS 13 9343 and Intel Core i7-5500U CPU.

Adding earlyprintk=efi revealed the kernel panic (thanks Nicholas for the tip!).

Photo: https://goo.gl/photos/JhkSTPMsurubqj8v8

[pdecat (pdecat)]

Issue resolved with today's build http://kernel.ubuntu.com/~kernel-ppa/mainline/daily/2017-06-03/

[jhoechtl (johann-hoechtl)]

Can this be confirmed to be solved? I have a Lenovo Yoga 720 13'' and I am able to boot with 4.10.0-32-generic but not with 4.10.0-33 nor 4.12.9-041209 nor 4.12.10-041210 from http://kernel.ubuntu.com/~kernel-ppa/mainline/?C=N;O=D