Re: [PATCH][2.6-mm] Fix 4G/4G X11/vm86 oops

["Martin J. Bligh" <mbligh@aracnet.com>]

>> Btw, you seem to compile with debugging, which makes the assembly 
>> language pretty much unreadable and accounts for most of the 
>> differences: the line numbers change. If you compile a kernel where the 
>> line numbers don't change (by commenting _out_ the printk rather than 
>> removing the whole line), your diff would be more readable.
> 
> Aha! Thanks for mentioning that, noted.
> 
>> Anyway, there are _zero_ differences.
>> 
>> Just for fun, try this: move the "printk()" to _below_ the "asm"  
>> statement. It will never actually get executed, but if it's an issue of
>> some subtle code or data placement things (cache lines etc), maybe that
>> also hides the oops, since all the same code and data will be generated, 
>> just not run...
> 
> Ok i just tried that and it still fails. Matt Mackall suggested i also try 
> writing a minimal printk which has the same effect.

The other thing I've found printks to hide before is timing bugs / races.
Unfortunately I can't see one here, but maybe someone else can ;-)
Maybe inserting a 1ms delay or something in place of the printk would
have the same effect?

M.