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

[Alejandro Colomar <alx@kernel.org>]

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On 2026-03-15T23:11:03+0100, 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!
> 
> 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.

Oops, actually, only the range-diff.

> 
> 
> 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
> 

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

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