Linux 6.10 Preps A Kernel Panic Screen - Sort Of A "Blue Screen of Death"

While systemd 255 last year introduced a "blue screen of death" inspired solution with systemd-bsod for presenting logged error messages full-screen, it's not appropriate for all errors. Systemd-bsod can work out for presenting full-screen messages in case of boot failures and other problems where user-space is alive. But the user-space code does little good in case of a kernel panic and similar issues bringing the system to a halt. Set to be introduced now with Linux 6.10 is a parallel "blue screen of death" like error presenting experience with the introduction of the DRM panic handler.

With kernel mode-setting drivers (KMS) being talked about for more than one decade has been the ability for Linux to present a "BSOD" in case of major issues. Over the past decade it's been brought up on and off again around a "BSOD" solution or DRM kernel oops viewer. Sent out today as part of the drm-misc-next patches to be submitted by DRM-Next for next month's Linux 6.10 merge window is a DRM panic handler.

A conventional Linux kernel panic with VT/FBCON support.

This DRM panic handler has been worked on by Red Hat and others for being able to display a message when a panic occurs. While the Linux kernel can already dump a kernel panic, that only works if VT/FBCON support is enabled for the kernel. For those that have been wanting to kill CONFIG_VT and the like, there isn't currently any way to view a kernel panic when it happens.

With the DRM panic handler that's been under review and several revisions the past several months, the message can be displayed when a panic occurs even if FBCON/VT is disabled.

At this stage the panic handler is quite basic and only works with a few Direct Rendering Manager drivers. The SimpleDRM, MGAG200, IMX, and AST DRM display drivers currently have the DRM panic handler support. With a kernel carrying the DRM panic support, the handler can be tested such as via the echo c > /proc/sysrq-trigger trigger. But with Linux kernel panics typically not happening too often, this handler will likely see little activity compared to the notorious days of Windows Blue Screen of Death messages.

This DRM panic driver support and other drm-panic work was sent out today as part of this drm-misc-next pull going to DRM-Next and therefore material for Linux 6.10. For Linux 6.10 the support appears quite basic but we'll see how it evolves over time.