Re: [PATCH v4] coccinelle: Detect clk_register() anti-pattern

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] coccinelle: clk_register: missing when != n constraints in bind_loop
--

commit 5a7f966954ec0e1e638d5df96a25b50558993fc6
Author: Guru Das Srinagesh <linux@gurudas.dev>

coccinelle: Detect clk_register() anti-pattern

This commit adds a Coccinelle semantic patch to detect and remove redundant
error messages logged after clk_register(), clk_hw_register(), and their
devm_/of_ variants fail.

> diff --git a/scripts/coccinelle/api/clk_register.cocci b/scripts/coccinelle/api/clk_register.cocci
> new file mode 100644
> index 0000000000000..01d272e2d96f7
> --- /dev/null
> +++ b/scripts/coccinelle/api/clk_register.cocci
> @@ -0,0 +1,262 @@

[ ... ]

> +@bind_loop depends on patch@
> +expression x, E;
> +identifier voidfn, n;
> +constant char[] c;
> +type T;
> +statement S, S_else;
> +@@
> +
> +  for (...;...;...) {
> +  ... when != n
> +- T n;
> +  ...
> +- n = E;
> +  ...
> +  x = \(clk_register\|devm_clk_register\|clk_hw_register\|devm_clk_hw_register\|of_clk_hw_register\)(...);
> +  if ( \( IS_ERR(x) \| x \| x < 0 \) )
> +(
> +-{
> +-voidfn(...,c,...,n,...);
> +S
> +-}
> +|
> +{
> +...
> +-voidfn(...,c,...,n,...);
> +...
> +}
> +)
> +  else S_else
> +  ... when != n
> +  }

[Severity: Medium]
Can the bind_loop rule delete the declaration and assignment of n when n is
still referenced elsewhere in the loop?

In SmPL, when != n only constrains the specific ellipsis to which it is
attached. Here, when != n is only placed before T n; (before n is in scope)
and after else S_else. The intermediate ellipses around n = E; and
voidfn(...), the registration call arguments, and the statements S and
S_else are not constrained.

If a loop uses n between n = E; and the end of the if/else block (for
example, passing n to the registration call or using it in S or S_else),
won't running this script in patch mode still remove T n; and n = E;,
leaving behind an undeclared identifier?

[ ... ]

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261018-cocci-clk-register-v4-1-ed611b1c0da6@gurudas.dev?part=1