Re: [crash] PANIC: double fault, error_code: 0x0

[Ingo Molnar]

* Ingo Molnar <mingo@xxxxxxxxxx> wrote:

> > (Also note that in my config NR_CPUS is at 128 - defconfigs are 64.)
> 
> The simplest padding I found is the one below - this indicates some sort of 
> section sizing or page table setup bug (or page alignment bug) and makes races and 
> other bugs less likely.
> 
> diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
> index 4ac952080869..ea992ca4e74f 100644
> --- a/arch/x86/entry/entry_64.S
> +++ b/arch/x86/entry/entry_64.S
> @@ -547,6 +547,8 @@ END(irq_entries_start)
>  	ud2
>  .Lokay_\@:
>  	addq $8, %rsp
> +#else
> +	.rep 64; nop; .endr

Also note that turning off CONFIG_UNWINDER_ORC also solves the crash. I did that 
in an attempt to get a different backtrace.

So it's either unwinder related, or seemingly minor changes to code 
alignment/placement will make the bug go away.

Thanks,

	Ingo