From: "Stone, Joshua I" <joshua.i.stone@intel.com>
To: "Mike Mason" <mmlnx@us.ibm.com>, <systemtap@sources.redhat.com>
Subject: RE: Pointer chain paranoia
Date: Tue, 14 Nov 2006 18:36:00 -0000 [thread overview]
Message-ID: <C56DB814FAA30B418C75310AC4BB279DEEF8FD@scsmsx413.amr.corp.intel.com> (raw)
On Tuesday, November 14, 2006 9:15 AM, Mike Mason wrote:
> I'm looking for opinions from the systemtap community... How paranoid
> should we be when following pointer chains in tapsets and scripts? I
> think we should use deref() unless we're absolutely sure there's no
> chance of referencing a null or bad pointer, but, of course, that'll
> add a lot of code. I'm not sure how you can ever be absolutely sure,
> particularly for longer chains. What guidance should we give tapset
> and script writers?
>
> Mike
I agree with you. Safety is always more important than efficiency,
especially in tapsets which may be used by non-guru users. Any
questionable pointers should be carefully dereferenced, e.g., parameters
passed to functions should be assumed bogus.
When a pointer is known to originate from a kernel source, like from
'current' or as a return value from a kernel function, then we might
relax a bit.
Josh
next reply other threads:[~2006-11-14 18:33 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2006-11-14 18:36 Stone, Joshua I [this message]
2006-11-14 19:23 ` Vara Prasad
2006-11-14 19:25 ` Roland McGrath
2006-11-14 21:21 ` Mike Mason
2006-11-15 10:06 ` Roland McGrath
-- strict thread matches above, loose matches on Subject: below --
2006-11-14 21:29 Stone, Joshua I
2006-11-14 18:33 Mike Mason
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