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

[Dirk Behme]

On 08.07.2026 07:41, Dirk Behme wrote:
> 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@xxxxxxxxx/T/#u

Arg, sorry, wrong link :(

https://lore.kernel.org/rust-for-linux/20260201155718.1623802-1-jason.kei.hall@xxxxxxxxx/

Sorry

Dirk

> 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@xxxxxxx/
>
> Best regards
>
> Dirk
>
>
> > Suggested-by: Miguel Ojeda <ojeda@xxxxxxxxxx>
> > Link: https://github.com/Rust-for-Linux/linux/issues/1191
> > Signed-off-by: Harish-CS <harish.cs.ss24@xxxxxxxxx>
> > ---
> >   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/) {