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From: Markus Elfring <Markus.Elfring@web.de>
To: Julia Lawall <julia.lawall@inria.fr>
Cc: Coccinelle <cocci@systeme.lip6.fr>
Subject: Re: [Cocci] Determination of failure predicates for selected function calls with SmPL?
Date: Wed, 25 Mar 2020 19:00:09 +0100	[thread overview]
Message-ID: <6658f112-0e62-498a-2947-165330d06bfe@web.de> (raw)
In-Reply-To: <alpine.DEB.2.21.2003251830510.2306@hadrien>

>> I have noticed the patch “tty: serial: fsl_lpuart: fix return value checking”.
>> https://lore.kernel.org/linux-serial/20200325090658.25967-2-michael@walle.cc/
…
> I'm not sure what there is to clarify.

Such an use case can point some software development challenges out.


> One can surely write rules that find this kind of problem,

I know this in principle.


> with a varying rate of false positives.

I am trying again to reduce this special case considerably.


> A simple approach would be to check all occurrences of if (!ret) for an
> integer-typed variable, because typically that is the success case.

I would like to increase the probability for generation of corresponding fixes.

The success predicate can be also the opposite if you would like to take
a Linux macro like access_ok() or valid pointers (after memory allocations
for example) into account.


> But sometimes people do put the success case under an if.

I am curious how often such source code variations should be considered.

Regards,
Markus
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  reply	other threads:[~2020-03-25 18:00 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-25 17:00 [Cocci] Determination of failure predicates for selected function calls with SmPL? Markus Elfring
2020-03-25 17:32 ` Julia Lawall
2020-03-25 18:00   ` Markus Elfring [this message]
2020-03-26  6:45   ` Markus Elfring

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