[Cocci] Coccinelle: fix parallel build with CHECK=scripts/coccicheck

SF Markus Elfring elfring at users.sourceforge.net
Tue Nov 14 10:08:18 CET 2017

> The problem on the Coccinelle side is that it uses a subdirectory with the
> name of the semantic patch to store standard output and standard error for
> the different threads.

It is occasionally good to know such background information.

> I didn't want to use a name with the pid, so that one could easily find
> this information while Coccinelle is running.

Do you mark these data as “hidden” in the file system?

> Normally the subdirectory is cleaned up when Coccinelle completes,
> so there is only one of them at a time.

I find that this can be insufficient occasionally.

> Maybe it is best to just add the pid.

I imagine that the storage algorithm could become better configurable
besides the parameters “--temp-files” and “--tmp-dir”.

> There is the risk that these subdirectories will accumulate if
> Coccinelle crashes in a way such that they don't get cleaned up,

I noticed such a situation a few times.

> but Coccinelle could print a warning if it detects this case,
> rather than failing.

I would appreciate such a software adjustment.

> Still I think it is useful to do something on the make coccicheck side,
> because there is no need for the double layer of parallelism.

Would you like to improve the corresponding documentation in any ways?


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