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

From: Jeremy Fitzhardinge
Date: Thu Sep 28 2006 - 02:50:12 EST

Andrew Morton wrote:
hm. Bigger vmlinux, smaller .text.


It means that we'll hit handle_BUG with that extra EIP pushed on the stack.
What does that do to the stack trace, and to the unwinder?
Dunno. I was hoping Andi would pop up with the appropriate CFI gunk, if necessary. But the reason for making it a call was to make it as unwindable as possible.

It'll also muck up the displayed EIP, not that that matters a lot (well, it
might matter a bit if the BUG is in an inlined function).

We could get the correct EIP by fishing it off the stack (and subtracting
five from it?)

Yes, that's possible.

Or we could assume that BUG doesn't return (it doesn't) and make that call
a jmp. But then we'd really lose the EIP.

Right. Or it could save the EIP along with the line and filename.

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