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

From: Jeremy Fitzhardinge
Date: Thu Sep 28 2006 - 06:27:25 EST

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.

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