On Thu, Aug 16, 2007 at 05:06:37PM -0500, Les Mikesell wrote: > Yet another unbootable kernel: 2.6.22.1-32.fc6 wouldn't boot on either a > Dell 1600sc or an IBM xserver 225. Is there some way to send a useful > bug report when the kernel just hangs during bootup? This comes up often enough, that it probably warrants a wiki page. There are a bunch of 'usual suspect' switches to try booting with to see if they help - first thing to do is get rid of the 'quiet' switch in the boot command line. We want as much info from the kernel as possible, and this just makes it impossible to debug. - acpi=off is a big hammer, and if that works, narrowing down by trying pci=noacpi instead may yield clues - nolapic and noapic are sometimes useful - Given it's new and still seeing quite a few changes, nohz=off may be worth testing. (Though this is F7 and above only) - initcall_debug will print the name of the kernel subsystems it calls during init, the last one will be the interesting one. - a majority of "won't boot" bugs are of the form where it fails to find the root filesystem. Quite often this ends up being a busted initrd for whatever reason. There's not really a good way to debug this other than to pull apart a good and bad one, and see if the bad one lacks modules that were in the good one for eg. - if stuff scrolls by too fast to catch interesting boot messages and you don't have a serial console, boot_delay=1000 will insert a pause after each print. - if you get no output at all from the kernel, sometimes booting with earlyprintk=vga can yield something of interest. Finally given that there can be pages of spew from this sort of debugging, if you lack a serial console to capture it, slowing down the printk's and taking a photo with a digital camera every pageful will save you a lot of transcribing. There's probably some other tricks that I'm forgetting right now too, but that's a good start. The problem with "won't boot" bugs is that the causes can be numerous so there's no one size fits all answer. Dave -- http://www.codemonkey.org.uk -- fedora-devel-list mailing list fedora-devel-list@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/fedora-devel-list
