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Re: loc2c-runtime deref()
- From: Roland McGrath <roland at redhat dot com>
- To: "Frank Ch. Eigler" <fche at redhat dot com>
- Cc: systemtap at sources dot redhat dot com
- Date: Thu, 18 Aug 2005 12:43:54 -0700 (PDT)
- Subject: Re: loc2c-runtime deref()
> The $target and $target->field extraction logic in the translator
> emits code that calls the macro deref() in src/runtime/loc2c-runtime.h
> to follow pointers. This macro appears to be tuned for accessing
> user-space (refers to uaccess.h's __get_user_asm). Is there good
> reason to believe it will continue to work even on kernel space
> pointers? Do those lower level macros provide sufficient detection of
> null and other invalid pointer dereferencing?
You are misunderstanding the code. Ignore the names in the implementation
details. The runtime macros are tailored specifically for kernel-mode
access, and their sole purpose is to catch invalid pointer references.