[OpenAFS] AFS 1.8.2 , bus error on FreeBSD

Benjamin Kaduk kaduk@mit.edu
Sat, 20 Apr 2019 01:50:43 -0500


On Mon, Apr 15, 2019 at 02:20:07PM +0200, Andreas Ladanyi wrote:
> Hi,
> 
> this entry in lwp.c helps. No bus error anymore with bos command.
> 
> +       /* Gross hack to change stack alignment. */
> +       stackptr += 8;
> 
> 
> Where is the patch from ?

It comes from my local tree from the last time I tried digging into this
issue.

I never managed to figure out what he source of the misalignment (or if you
prefer, offset) was, since the starting allocation for the stack space
should always be much more aligned than 8 bytes.  Since I didn't understand
why it worked, I wasn't able to write a commit message for the change that
I was comfortable submitting for review.

IIRC I only needed to have the ports collection do anything for clang,
since (at least) the in-tree gcc 4.2.1 would not emit the fancy
instructions that have higher alignment requirements, at least not at -O0.
And I'd rather spend time getting rid of LWP for everyone than tracking
down the FreeBSD-specific bug.

-Ben