Re: [PATCH] Put the BUG __FILE__ and __LINE__ info out of line

[Jeremy Fitzhardinge <jeremy@goop.org>]

Andrew Morton wrote:
> Plan #17 is to just put the BUG inline and then put the EIP+file*+line into
> a separate section, then search that section at BUG time to find the record
> whose EIP points back at this ud2a.
>   

Sure, but it seems a bit complex for this; I think simpler is better 
when the kernel has got itself into an iffy state.

> It's a bit messy for modules, but it minimises the .text impact and keeps
> disassembly happy, no?
>   
I'm not quite sure I understand your concern.  You're worried about the 
size increase to vmlinux in the case where you specify 
CONFIG_DEBUG_BUGVERBOSE?  Seems to me that if you specify it, you're 
willing to give up some kernel space for it, and adding 5 bytes/BUG 
isn't a huge deal (that's about 10k extra on my kernel).

Especially since the file+line info is mostly redundant anyway (since 
the kernel can tell you what a function an EIP is in), and completely 
redunant if you have debug info.  I guess its mostly useful so you can 
interpret the the bug message without access to kernel image.

> And if done right it can probably be used by other architectures.
>   

DWARF seems like the better answer to me.


    J