Bug#502845: open-iscsi: login fails using 64-bit kernel with 32-bit userland

[Jonathan Nieder <jrnieder@gmail.com>]

Hi Julia,

Julia Longtin wrote:

> [Subject: what gives]

Please keep in mind that these appear as emails in a crowded inbox,
where an informative subject can be a good way to provide valuable
context.

> reading the iscsi mailing list link posted, it appears the final patch
> addresses the issue concerned, and works on 32/32, 32/64 and 64/64.

Which patch --- Lisa's userspace or kernel patch?

Both break ABI.

While the patches are both useful for insight, the userspace patch, if
widely deployed, would make the kernel interface impossible to fix.
Please make sure anyone applying it knows what they are doing.  The
test it uses for the broken ABI is

	if(strcmp(uname_data.machine, "x86_64") != 0) 
	    fix_32bit_kernel_structs = 1; 

That means:

 * once the x86_64 kernel is fixed to use the correct compat ABI,
   this patch will break userspace!

 * the test is wrong anyway.  On other 64-bit platforms with compat
   support the problem still exists just like before.

However, if you *know* that you will only be using broken kernels then
it is safe to use as a userspace workaround.

>         what's happening with this bug?

The next step is for someone to write a patch to fix the compat
interface on the kernel side.  I explained one way to do this at [1];
I would love to work on that, but unfortunately I have not had a lot
of time recently, so I won't be brokenhearted if someone else gets to
this first.

Thanks and hope that helps,
Jonathan

[1] http://bugs.debian.org/cgi-bin/bugreport.cgi?msg=131;bug=502845