Kernel

• Next — Bleeding edge kernels with features pending to be merged into next mainline release.

https://www.kernel.org/doc/man-pages/linux-next.html || linux-next-git^AUR

• Longterm 4.14 — Long-term support (LTS) Linux 4.14 kernel and modules.

https://www.kernel.org/ || linux-lts414^AUR

• Liquorix — Kernel replacement built using Debian-targeted configuration and the Zen kernel sources. Designed for desktop, multimedia, and gaming workloads, it is often used as a Debian Linux performance replacement kernel. Damentz, the maintainer of the Liquorix patchset, is a developer for the Zen patchset as well.

https://liquorix.net || linux-lqx^AUR

• Repository by pf-kernel developer post-factum
• Repository, , by pf-kernel fork developer Thaodan
• by yurikoles

• Realtime kernel — Maintained by a small group of core developers led by Ingo Molnar. This patch allows nearly all of the kernel to be preempted, with the exception of a few very small regions of code ("raw_spinlock critical regions"). This is done by replacing most kernel spinlocks with mutexes that support priority inheritance, as well as moving all interrupt and software interrupts to kernel threads.

https://wiki.linuxfoundation.org/realtime/start || linux-rt^AUR, linux-rt-lts^AUR

A kernel panic occurs when the Linux kernel enters an unrecoverable failure state. The state typically originates from buggy hardware drivers resulting in the machine being deadlocked, non-responsive, and requiring a reboot. Just prior to deadlock, a diagnostic message is generated, consisting of: the machine state when the failure occurred, a call trace leading to the kernel function that recognized the failure, and a listing of currently loaded modules. Thankfully, kernel panics do not happen very often using mainline versions of the kernel--such as those supplied by the official repositories--but when they do happen, you need to know how to deal with them.

If a kernel panic occurs very early in the boot process, you may see a message on the console containing "Kernel panic - not syncing:", but once Systemd is running, kernel messages will typically be captured and written to the system log. However, when a panic occurs, the diagnostic message output by the kernel is almost never written to the log file on disk because the machine deadlocks before gets the chance. Therefore, the only way to examine the panic message is to view it on the console as it happens (without resorting to setting up a kdump crashkernel). You can do this by booting with the following kernel parameters and attempting to reproduce the panic on tty1:

systemd.journald.forward_to_console=1 console=tty1

It is possible to make a best guess as to what subsystem or module is causing the panic using the information in the diagnostic message. In this scenario, we have a panic on some imaginary machine during boot. Pay attention to the lines highlighted in bold:

1. Indicates the type of error that caused the panic. In this case it was a programmer bug.
2. Indicates that the panic happened in a function called fw_core_init in module firewire_core.
3. Indicates that firewire_core was the latest module to be loaded.
4. Indicates that the function that called function fw_core_init was do_one_initcall.
5. Indicates that this oops message is, in fact, a kernel panic and the system is now deadlocked.

We can surmise then, that the panic occurred during the initialization routine of module firewire_core as it was loaded. (We might assume then, that the machine's firewire hardware is incompatible with this version of the firewire driver module due to a programmer error, and will have to wait for a new release.) In the meantime, the easiest way to get the machine running again is to prevent the module from being loaded. We can do this in one of two ways:

• If the module is being loaded during the execution of the initramfs, reboot with the kernel parameter .
• Otherwise reboot with the kernel parameter .

You will need a root shell to make changes to the system so the panic no longer occurs. If the panic occurs on boot, there are several strategies to obtain a root shell before the machine deadlocks:

• Reboot with the kernel parameter emergency, , or to receive a prompt to login just after the root filesystem is mounted and is started.

• Reboot with the kernel parameter rescue, , , , , or to receive a prompt to login just after local filesystems are mounted.
• Reboot with the kernel parameter systemd.debug_shell to obtain a very early root shell on tty9. Switch to it with by pressing .
• Experiment by rebooting with different sets of kernel parameters to possibly disable the kernel feature that is causing the panic. Try the "old standbys" and .

• As a last resort, boot with an Arch Linux installation medium and mount the root filesystem on then execute as the root user.
• Disable the service or program that is causing the panic, roll-back a faulty update, or fix a configuration problem.

See General troubleshooting#Debugging regressions.

Try linux-mainline^AUR to check if the issue is already fixed upstream. The stickied comment also mentions a repository which contains already built kernels, so it may not be necessary to build it manually, which can take some time.

It may also be worth considering trying the LTS kernel () to debug issues which did not appear recently. Older versions of the LTS kernel can be found in the Arch Linux Archive.

If the issue still persists, bisect and report the bug on the kernel bugzilla. It is important to try the "vanilla" version without any patches to make sure it is not related to them. If a patch causes the issue, report it to the author of the patch.