Re: [PATCH] scripts: Coccinelle script for pci_free_consistent()

[Julia Lawall <julia.lawall@lip6.fr>]

On Wed, 8 May 2013, strnape1@fel.cvut.cz wrote:

> Alright, so should I make a patch from it?

Could you check that it does what you expect?  If everything is OK, then
you can make a patch.

thanks,
julia

> Quoting Julia Lawall <julia.lawall@lip6.fr>:
>
> > Here is a proposal.  Some features:
> >
> > * It assumes that the result of pci_alloc_consistent is null tested, and
> > doesn't report any problems before that.
> >
> > * It uses exists rather than forall, to find a bug when there is a problem
> > on just one execution path.
> >
> > * It gives no warning if the return value is stored elsewhere or is freed
> > under some kinds of if.
> >
> > * It recognizes 1 as a success value.
> >
> > On linux-next, this gives 10 reports.  At least half of them are false
> > positives, mostly due to interprocedural effects, which this rule does not
> > at all take into account.
> >
> > julia
> >
> > /// Find missing pci_free_consistent for every pci_alloc_consistent.
> > ///
> > // Confidence: Moderate
> > // Copyright: (C) 2013 Petr Strnad.  GPLv2.
> > // URL: http://coccinelle.lip6.fr/
> > // Keywords: pci_free_consistent, pci_alloc_consistent
> > // Options: --no-includes --include-headers
> >
> > virtual report
> > virtual org
> >
> > @search@
> > local idexpression id;
> > expression x,y,z,e;
> > position p1,p2;
> > type T;
> > @@
> >
> > id = pci_alloc_consistent@p1(x,y,&z)
> > ... when != e = id
> > if (id = NULL || ...) { ... return ...; }
> > ... when != pci_free_consistent(x,y,id,z)
> >    when != if (id) { ... pci_free_consistent(x,y,id,z) ... }
> >    when != if (y) { ... pci_free_consistent(x,y,id,z) ... }
> >    when != e = (T)id
> >    when exists
> > (
> > return 0;
> > |
> > return 1;
> > |
> > return id;
> > |
> > return@p2 ...;
> > )
> >
> > @script:python depends on report@
> > p1 << search.p1;
> > p2 << search.p2;
> > @@
> >
> > msg = "ERROR: missing pci_free_consistent; pci_alloc_consistent on line %s
> > and return without freeing on line %s" % (p1[0].line,p2[0].line)
> > coccilib.report.print_report(p2[0],msg)
> >
> > @script:python depends on org@
> > p1 << search.p1;
> > p2 << search.p2;
> > @@
> >
> > msg = "ERROR: missing pci_free_consistent; pci_alloc_consistent on line %s
> > and return without freeing on line %s" % (p1[0].line,p2[0].line)
> > cocci.print_main(msg,p1)
> > cocci.print_secs("",p2)
>
>
>
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