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I'm running Fedora 31 and compiled a kernel with acs patch I needed according to this recipe, but it didn't boot at all(*). I followed these steps:

# rpmdev-setuptree
# koji download-build --arch=src kernel-5.4.18-200.fc31
# rpm -Uhv kernel-5.4.18-200.fc31.src.rpm
# cd SPECS/

... (here I applied the acs patch, but I also tried a clean build, i.e. without any action here)

# dnf builddep kernel.spec
# rpmbuild -bb kernel.spec
# cd ../RPMS
# rpm -ihv kernel-5.4.18-200.fc31.x86_64.rpm kernel-core-5.4.18-200.fc31.x86_64.rpm kernel-modules-5.4.18-200.fc31.x86_64.rpm kernel-modules-extra-5.4.18-200.fc31.x86_64.rpm kernel-modules-internal-5.4.18-200.fc31.x86_64.rpm kernel-devel-5.4.18-200.fc31.x86_64.rpm
# reboot

Apart from a few objtool: unreachable instruction .... warnings (which I was lead to believe shouldn't be problematic for normal operation), all output appeared normal and all rpms were built.

After the GRUB menu I literally see nothing (only a blinking cursor), that is, after I disabled EDD. Before disabling EDD, I just saw the first logging line mentioning EDD, and the kernel hung immediately afterwards.

Increasing loglevel or installing the -debug kernel (from the packages built along the above kernel) doesn't make any difference, i.e. I don't get a single line of debug info, probably because the kernel halts before even starting(?).

My cmdline is applied to all kernels (with grubby --update-kernel=ALL --args=...) and reads BOOT_IMAGE=(hd0,msdos1)/vmlinuz-5.4.10-200.fc31.x86_64 root=/dev/mapper/fedora_1nnoserv-root ro resume=/dev/mapper/fedora_1nnoserv-swap rd.lvm.lv=fedora_1nnoserv/root rd.lvm.lv=fedora_1nnoserv/swap intel_iommu=on pcie_acs_override=downstream,multifunction iommu=pt rd.driver.pre=vfio-pci video=vesafb:off vga=normal nofb nomodeset edd=off loglevel=7

(Obviously this example was obtained from the standard kernel which could normally boot. The options disabling all fb stuff is because it's a headless server for which I intend to use GPU passthrough to a kvm VM, so I want to avoid any fb drivers occupying the GPU before vfio is loaded).

All I could find on the net appears to be related to boot errors later in the boot process, but in my case I have no idea where to start because there is zero output.

  • This is still an issue, anyone out there have an idea? – ppenguin Feb 27 at 17:27

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