Re: [gentoo-user] Boot freeze/kthreadd stack trace - AMD_PMU_INIT

[Fernando Rodriguez]

On 11/21/2016 01:15 AM, Taiidan@×××.com wrote:
> Specs:
> blob free coreboot on a kgpe-d16 (amd opteron)
>
>
> Happens with both the livecd/usb and a kernel I compiled on another
> machine (however with that one I simply get a black screen and a bootloop)

Look at CONFIG_PANIC_TIMEOUT. If it's set to anything other than 0 your
kernel will reboot itself on panic after the timeout. It's probably
panicing when initialing the video drivers since you get a blank screen
so you'll probably want to boot with a vga fb driver (blacklist or
delete all other video modules) and post the backtrace if it still panics.


> Other distros kernels work fine, it is just gentoo.

Then I suggest you try grabbing the kernel's config file from another
distro and use that as a starting point to configure your kernel

> The livecd and compiled kernel work fine on all my other computers/VMM's.
>
> Upon loading I get to amd performance counters, it freezes and 5-10 secs
> later I receive stack trace for kthreadd "hung" (amd_pmu_init - seems to
> be the primary reason) I never get to a login prompt.
>
> It isn't microcode related as I removed the microcode packages from the
> other distros I tried.
>
> Any ideas? Is there any additional info that would be helpful? How can I
> dump the boot text?

It's gonna be trial and error. Keep disabling features and try a
different kernel version (the one that worked with other distros) until
you pinpoint the problem. The only hints you got are the panic backtrces
and boot output. Then file a bug.

As for dumping the boot output if you can't get to userland I think the
only way is with a serial or net console. Also look at
CONFIG_BOOT_PRINTK_DELAY, it can setup a delay before every printk
message so you at least get time to read it.

-- 

Fernando Rodriguez