Re: [cocci] [PATCH v3 (resend)] scripts/coccinelle: Add script for using ARRAY_END()

[Alejandro Colomar <alx@kernel.org>]

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Hi Julia,

> Date: 2026-09-27 11:21:54+0200
> From: Julia Lawall <julia.lawall@inria.fr>
>
> 
> 
> On Tue, 22 Sep 2026, Alejandro Colomar wrote:
> 
> > Recently, we added an ARRAY_END() macro to simplify finding a pointer
> > one past the last element in an array.  Such a pointer is often called
> > the 'end', and thus the macro name.
> >
> > Make it easy to find more places where that macro should be used.
> >
> > See also:
> > 436debc9cad8 ("array_size.h: add ARRAY_END()")
> > 8118f197b7b7 ("mm: fix benign off-by-one bugs")
> > a9e5620c9a9e ("kernel: fix off-by-one benign bugs")
> > 61e9210e2392 ("mm: use ARRAY_END() instead of open-coding it")
> >
> > Cc: Kees Cook <kees@kernel.org>
> > Cc: Markus Elfring <Markus.Elfring@web.de>
> > Cc: Julia Lawall <Julia.Lawall@inria.fr>
> > Cc: Nicolas Palix <nicolas.palix@imag.fr>
> > Signed-off-by: Alejandro Colomar <alx@kernel.org>
> > ---
> >
> >
> > Hi Julia,
> >
> > Resent the patch now, as you asked me to do.
> 
> Applied, thanks.
> 
> Afterwards, I made two changes:
> 
>     * Add disable zero_multiple_format to each rule to avoid considering
>     the possibility that an array index is expressed using '\0'
> 
>     * Omit outer parentheses on context and org/report rules that
>     only match ubt don't transform, since matching a subterm gives
>     the same result whether or not the parentheses are present.

Thanks!!

I'll look at the patch to see how it changed, out of curiosity.  :)


Have a lovely day!
Alex

> 
> julia
> 
> 
> >
> >
> > Cheers,
> > Alex
> >
> > Here's the original message that came with the patch:
> >
> > Hi!
> >
> > This v3 only has one change: I've removed the comment about the false
> > negatives.  They were due to spatch(1) not being able to correctly parse
> > unrelated code elsewhere.
> >
> > See range-diff and interdiff at the bottom.
> >
> >
> > Have a lovely night!
> > Alex
> >
> >  scripts/coccinelle/misc/array_end.cocci | 73 +++++++++++++++++++++++++
> >  1 file changed, 73 insertions(+)
> >  create mode 100644 scripts/coccinelle/misc/array_end.cocci
> >
> > diff --git a/scripts/coccinelle/misc/array_end.cocci b/scripts/coccinelle/misc/array_end.cocci
> > new file mode 100644
> > index 00000000..88c664de
> > --- /dev/null
> > +++ b/scripts/coccinelle/misc/array_end.cocci
> > @@ -0,0 +1,73 @@
> > +// SPDX-License-Identifier: GPL-2.0-only
> > +/// Use ARRAY_END instead of an expression derived from ARRAY_SIZE
> > +//
> > +// Confidence: High
> > +// Copyright: 2026, Alejandro Colomar <alx@kernel.org>
> > +// Options: --no-includes --include-headers
> > +
> > +virtual patch
> > +virtual context
> > +virtual org
> > +virtual report
> > +
> > +@depends on context@
> > +type T;
> > +T[] a;
> > +expression b;
> > +@@
> > +(
> > +* (a + ARRAY_SIZE(a))
> > +|
> > +* (&a[0] + ARRAY_SIZE(a))
> > +|
> > +* (&a[ARRAY_SIZE(a)])
> > +|
> > +* (&a[ARRAY_SIZE(a) - b])
> > +)
> > +
> > +@depends on patch@
> > +type T;
> > +T[] a;
> > +expression b;
> > +@@
> > +(
> > +- (a + ARRAY_SIZE(a))
> > ++ ARRAY_END(a)
> > +|
> > +- (&a[0] + ARRAY_SIZE(a))
> > ++ ARRAY_END(a)
> > +|
> > +- (&a[ARRAY_SIZE(a)])
> > ++ ARRAY_END(a)
> > +|
> > +- (&a[ARRAY_SIZE(a) - b])
> > ++ ARRAY_END(a) - b
> > +)
> > +
> > +@r depends on org || report@
> > +type T;
> > +T[] a;
> > +expression b;
> > +position p;
> > +@@
> > +(
> > + (a@p + ARRAY_SIZE(a))
> > +|
> > + (&a[0]@p + ARRAY_SIZE(a))
> > +|
> > + (&a[ARRAY_SIZE(a)]@p)
> > +|
> > + (&a[ARRAY_SIZE(a)@p - b])
> > +)
> > +
> > +@script:python depends on org@
> > +p << r.p;
> > +@@
> > +
> > +coccilib.org.print_todo(p[0], "WARNING should use ARRAY_END")
> > +
> > +@script:python depends on report@
> > +p << r.p;
> > +@@
> > +
> > +coccilib.report.print_report(p[0], "WARNING: opportunity for ARRAY_END")
> >
> > Range-diff:
> > 1:  9fd8d3d1 ! 1:  2ae22f8b scripts/coccinelle: Add script for using ARRAY_END()
> >     @@ scripts/coccinelle/misc/array_end.cocci (new)
> >      +//
> >      +// Confidence: High
> >      +// Copyright: 2026, Alejandro Colomar <alx@kernel.org>
> >     -+// Comments: No known false positives, but has a few false negatives
> >      +// Options: --no-includes --include-headers
> >      +
> >      +virtual patch
> > --
> > 2.53.0
> >
> >
> > ----- End forwarded message -----
> >
> > --
> > <https://www.alejandro-colomar.es>
> >

-- 
<https://www.alejandro-colomar.es>

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