Zack's Kernel News
Zack's Kernel News

Chronicler Zack Brown reports on the little links that bring us closer within the Linux kernel community.
Best Laid Plans
When the Linux kernel encountered a runtime warning, Alexander Popov didn't like that it had only two possible responses: Ignore the whole thing, or panic (i.e., crash 'n' burn). The crash 'n' burn response would trigger if the user had set the panic_on_warn
flag. Otherwise, the warning would be ignored. Alexander felt that a nice middle-of-the-road response would be for the kernel to simply stop whatever it was that caused the warning. This way at least the system could still function.
Alexander also pointed out some security problems with the current state of affairs. He said that to avoid the extreme response, "panic_on_warn is usually disabled on production systems." And, "From a security point of view, kernel warning messages provide a lot of useful information for attackers. Many GNU/Linux distributions allow unprivileged users to read the kernel log, so attackers use kernel warning info leak in vulnerability exploits."
Alexander proposed a compromise so that system administrators and distribution maintainers would not feel the need to completely disable all responses to kernel warnings. He said, "Let's introduce the pkill_on_warn boot parameter. If this parameter is set, the kernel kills all threads in a process that provoked a kernel warning. This behavior is reasonable from a safety point of view described above. It is also useful for kernel security hardening because the system kills an exploit process that hits a kernel warning."
[...]
Buy this article as PDF
(incl. VAT)
Buy Linux Magazine
Subscribe to our Linux Newsletters
Find Linux and Open Source Jobs
Subscribe to our ADMIN Newsletters
Support Our Work
Linux Magazine content is made possible with support from readers like you. Please consider contributing when you’ve found an article to be beneficial.

News
-
System76 Releases COSMIC Alpha 7
With scores of bug fixes and a really cool workspaces feature, COSMIC is looking to soon migrate from alpha to beta.
-
OpenMandriva Lx 6.0 Available for Installation
The latest release of OpenMandriva has arrived with a new kernel, an updated Plasma desktop, and a server edition.
-
TrueNAS 25.04 Arrives with Thousands of Changes
One of the most popular Linux-based NAS solutions has rolled out the latest edition, based on Ubuntu 25.04.
-
Fedora 42 Available with Two New Spins
The latest release from the Fedora Project includes the usual updates, a new kernel, an official KDE Plasma spin, and a new System76 spin.
-
So Long, ArcoLinux
The ArcoLinux distribution is the latest Linux distribution to shut down.
-
What Open Source Pros Look for in a Job Role
Learn what professionals in technical and non-technical roles say is most important when seeking a new position.
-
Asahi Linux Runs into Issues with M4 Support
Due to Apple Silicon changes, the Asahi Linux project is at odds with adding support for the M4 chips.
-
Plasma 6.3.4 Now Available
Although not a major release, Plasma 6.3.4 does fix some bugs and offer a subtle change for the Plasma sidebar.
-
Linux Kernel 6.15 First Release Candidate Now Available
Linux Torvalds has announced that the release candidate for the final release of the Linux 6.15 series is now available.
-
Akamai Will Host kernel.org
The organization dedicated to cloud-based solutions has agreed to host kernel.org to deliver long-term stability for the development team.