Re: [cocci] bug: Matching a specific declarer actually matches any declarer

On Mon, 1 Dec 2025, Tobias Deiminger wrote:

> Hi,
>
> to reproduce the issue, try mutex2.cocci from coccinellery [1] with the code
> below.
>
> Expectation: Only spin_lock calls where the variable was declared with
> DEFINE_MUTEX() are patched.
>
> Actual: The declarer name seems to be ignored. All spin_lock calls are
> patched, regardless of the declarer name
>
> // mutex2.c
> DEFINE_MUTEX(my_mutex);
> OTHER_DECLARER(other_mutex);
>
> void main() {
>     // this should be changed, declarer was DEFINE_MUTEX
>     spin_lock(&my_mutex);
>
>     // this should not be changed, declarer was OTHER_DECLARER
>     spin_lock(&other_mutex)
> }
>
> // mutex2.cocci
> @def@
> declarer DEFINE_MUTEX;

This should be declarer name, not declarer.  Declarer matches any declarer
name.

julia

> identifier m;
> @@
>
> DEFINE_MUTEX(m);
>
> @@
> identifier def.m;
> @@
>
> (
> - spin_lock(&m)
> + mutex_lock(&m)
> |
> - spin_unlock(&m)
> + mutex_unlock(&m)
> )
>
> The unexpected result:
>
> $ spatch --sp-file mutex2.cocci mutex2.c
> init_defs_builtins: /usr/lib/coccinelle/standard.h
> HANDLING: mutex2.c
> SPECIAL NAMES: adding OTHER_DECLARER as a declarer
> diff =
> --- mutex2.c
> +++ /tmp/cocci-output-71243-6eaa4e-my.c
> @@ -3,8 +3,8 @@ OTHER_DECLARER(other_mutex);
>
>  void main() {
>      // this should be changed, declarer was DEFINE_MUTEX
> -    spin_lock(&my_mutex);
> +    mutex_lock(&my_mutex);
>
>      // this should not be changed, declarer was OTHER_DECLARER
> -    spin_lock(&other_mutex)
> +    mutex_lock(&other_mutex)
>  }
>
>
> Could you confirm, and maybe suggest a workaround? I used the coccinellery
> example as reproducer because it's public, but actually stumbled upon the
> issue in a simpler case: I searched for all occurrences of
> DEVICE_ATTR_RO(attr) in the Linux kernel, but actually found every place where
> *any* macro was used to declare something.
>
> Cheers
> Tobias
>
> PS: I'm using spatch 1.3 from Debian trixie.
>
> [1] https://github.com/coccinelle/coccinellery/blob/master/cris/mutex2.cocci
>