Re: [PATCH] x86_64: another fix for canonical RIPs during signalhandling

From: Alan Cox
Date: Fri Jun 23 2006 - 10:35:46 EST


Ar Gwe, 2006-06-23 am 15:32 +0200, ysgrifennodd Willy Tarreau:
> If I understand it well, an application which maps address 0 has no way to
> be notified that the kernel detected a corrupted stack pointer.

A debugger can deal with this corner case if it ever needs to be careful
mapping and remapping of the page. Very few apps map data at the zero
page and those that do usually map a single zero page which probably
isn't PROT_EXEC anyway.

(The usual case is to speed up pointer chain walking by knowing that
NULL->NULL->... is always NULL)

Alan

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