Re: [PATCH v2] hypfs: add ASSERT_UNREACHABLE() in hypfs_get_entry_rel()

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 28/04/2026 7:19 pm, Dmytro Prokopchuk1 wrote:
> The statement 'return ERR_PTR(-ENOENT);' on the final line of the
> function 'hypfs_get_entry_rel()' is unreachable because the logic within
> the infinite loop 'for (;;)' provides all possible exit paths for the
> function. So there is no execution path to exit the loop and reach the
> final that statement.
>
> This unreachable code violates MISRA C Rule 2.1 which states: "A project
> shall not contain unreachable code".
>
> To fix that and potential compilers "control reaches end of non-void
> function" warning, mark the code path as unreachable using macro
> 'ASSERT_UNREACHABLE()'.
>
> Signed-off-by: Dmytro Prokopchuk <dmytro_prokopchuk1@xxxxxxxx>
> ---
> Changes in v2:
> - add ASSERT_UNREACHABLE() before the final return statement instead of 
> removing it
> Test CI pipeline:
> https://gitlab.com/xen-project/people/dimaprkp4k/xen/-/pipelines/2485661910
> Link to v1:
> https://patchew.org/Xen/341811ced2943fb79d0235c27781c564c7bdaf02.1775749146.git.dmytro._5Fprokopchuk1@xxxxxxxx/
> ---
>  xen/common/hypfs.c | 1 +
>  1 file changed, 1 insertion(+)
>
> diff --git a/xen/common/hypfs.c b/xen/common/hypfs.c
> index cdf4ee0171..02fb234568 100644
> --- a/xen/common/hypfs.c
> +++ b/xen/common/hypfs.c
> @@ -348,6 +348,7 @@ static struct hypfs_entry *hypfs_get_entry_rel(struct 
> hypfs_entry_dir *dir,
>          dir = container_of(entry, struct hypfs_entry_dir, e);
>      }
>  
> +    ASSERT_UNREACHABLE();
>      return ERR_PTR(-ENOENT);
>  }
>  

No.  This is absurd.

Not to mention that you are *definitely* not fixing the stated MISRA rule.

~Andrew