Re: [PATCH] checkpatch: warn on Rust unwrap and expect calls

[Dirk Behme <dirk.behme@de.bosch.com>]

Hi Harish,

On 07.07.2026 10:21, Harish-CS wrote:
> Rust panic paths are discouraged in kernel code because panics currently
> lead to BUG-like behavior. Add a checkpatch warning for newly added Rust
> uses of unwrap(), unwrap_err(), expect() and expect_err() so contributors
> notice them during patch review.

We've had something similar some month ago, already. Maybe you like to 
check that discussion:

https://lore.kernel.org/rust-for-linux/20260707082104.90951-1-harish.cs.ss24@gmail.com/T/#u

If I remember correctly the main concern was how to filter out the 
allowed/required usages. I think the example used that time was

https://lore.kernel.org/rust-for-linux/20260131154016.270385-3-shivamklr@cock.li/

Best regards

Dirk


> Suggested-by: Miguel Ojeda <ojeda@kernel.org>
> Link: https://github.com/Rust-for-Linux/linux/issues/1191
> Signed-off-by: Harish-CS <harish.cs.ss24@gmail.com>
> ---
>   Documentation/dev-tools/checkpatch.rst | 4 ++++
>   scripts/checkpatch.pl                  | 9 +++++++++
>   2 files changed, 13 insertions(+)
> 
> diff --git a/Documentation/dev-tools/checkpatch.rst b/Documentation/dev-tools/checkpatch.rst
> index 6139a08c34cd..afa9787c1b9f 100644
> --- a/Documentation/dev-tools/checkpatch.rst
> +++ b/Documentation/dev-tools/checkpatch.rst
> @@ -303,6 +303,10 @@ API usage
>   
>       See: https://www.kernel.org/doc/html/latest/process/deprecated.html#bug-and-bug-on
>   
> +  **RUST_PANIC_METHODS**
> +    Rust methods that panic, such as unwrap() and expect(), should be
> +    avoided.  Handle the error explicitly instead.
> +
>     **CONSIDER_KSTRTO**
>       The simple_strtol(), simple_strtoll(), simple_strtoul(), and
>       simple_strtoull() functions explicitly ignore overflows, which
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 2b7a42bbdd94..5bdb065370ea 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -3972,6 +3972,15 @@ sub process {
>   			}
>   		}
>   
> +# avoid Rust panicking methods
> +		if ($realfile =~ /\.rs$/ &&
> +		    $line =~ /^\+.*\.(?:unwrap(?:_err)?|expect(?:_err)?)\s*\(/) {
> +			my $msg_level = \&WARN;
> +			$msg_level = \&CHK if ($file);
> +			&{$msg_level}("RUST_PANIC_METHODS",
> +				      "Avoid Rust panicking methods such as unwrap() and expect(); handle the error instead\n" . $herecurr);
> +		}
> +
>   # check for .L prefix local symbols in .S files
>   		if ($realfile =~ /\.S$/ &&
>   		    $line =~ /^\+\s*(?:[A-Z]+_)?SYM_[A-Z]+_(?:START|END)(?:_[A-Z_]+)?\s*\(\s*\.L/) {