[SystemSafety] When malloc() Never Returns NULL

[David MENTRE]

Hello,

The USS Yorktown is a good example, thank you for the reminder. I agree that one can underestimate the criticality of some applications.

Best regards,
David Mentré 

> Le 11 mai 2023 à 20:58, Derek M Jones <derek at knosof.co.uk> a écrit :
> 
> David,
> 
>> How is it relevant to System Safety (topic of this list)? This paper is interesting but as far as I know, safety critical programs are not executed on generic OS mentioned by this paper but real-time OS or bare metal. Moreover, such programs 
> 
> The divide-by zero error on the USS Yorktown springs to mind
> https://medium.com/dataseries/when-smart-ships-divide-by-zer0-uss-yorktown-4e53837f75b2
> 
>> would never do dynamic memory allocation or only at program startup. In my view, the recommendations of this paper (in particular using x family functions that assume allocation always succeed or terminate the application) are not valid in safety critical context: the handling of memory allocation failure should be considered and handled properly.
> 
> I continue to be surprised by the complexity of hardware/software
> being used in safety related applications.
> 
> Every now and again something considered as not safety critical fails,
> and an unnoticed dependency suddenly appears.
> 
> I know of (not used in safety critical, as far as I know) programs that
> handle malloc returning NULL by sensibly closing things down.  The
> idea that malloc failing might result in the cleanup never occurring,
> because the process is killed by the OS, is something relatively new.
> 
>> Best regards,
>> David Mentré
>>>> Le 11 mai 2023 à 12:58, Derek M Jones <derek at knosof.co.uk> a écrit :
>>> 
>>> All,
>>> 
>>> Coding guidelines have been telling developers to
>>> check the return value of malloc forever.
>>> 
>>> It certainly used to make a difference, but it looks
>>> as if out-of-memory is becoming a thing of the past,
>>> at least on the desktop.
>>> 
>>> "When malloc() Never Returns NULL -- Reliability as an Illusion"
>>> https://arxiv.org/abs/2208.08484
>>> 
>>> -- 
>>> Derek M. Jones           Evidence-based software engineering
>>> blog:https://shape-of-code.com
>>> _______________________________________________
>>> The System Safety Mailing List
>>> systemsafety at TechFak.Uni-Bielefeld.DE
>>> Manage your subscription: https://lists.techfak.uni-bielefeld.de/mailman/listinfo/systemsafety
>> _______________________________________________
>> The System Safety Mailing List
>> systemsafety at TechFak.Uni-Bielefeld.DE
>> Manage your subscription: https://lists.techfak.uni-bielefeld.de/mailman/listinfo/systemsafety
> 
> -- 
> Derek M. Jones           Evidence-based software engineering
> blog:https://shape-of-code.com
> _______________________________________________
> The System Safety Mailing List
> systemsafety at TechFak.Uni-Bielefeld.DE
> Manage your subscription: https://lists.techfak.uni-bielefeld.de/mailman/listinfo/systemsafety