Kernel/Compiler bug

[Larry Baird]

Ryan,

On Wed, Oct 01, 2014 at 12:46:35AM -0400, Ryan Stone wrote:
> This may not be a compiler bug.  A quick look at the esp values
> provided in that backtrace shows that at least 7KB has been used on
> the stack.  The stack for kernel threads is only 8KB, and a stack
> overflow can cause a double fault like that.
> 
> My suspicion would be that without optimizations on clang uses a lot
> more stack space and you push over the limit.  There's a kernel build
> option for the stack size that you could change to confirm.  I believe
> that it's called KSTACK_PAGES.  Try increasing it to 4.
Good catch.  Increasing KSTACK_PAGES does fix the issue.  I wonder with
optimization, how close to stack overflow does the kernel get during boot?

Thank you,
Larry

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Larry Baird
Global Technology Associates, Inc. 1992-2012 	| http://www.gta.com
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