Re: [PATCH v1 3/3] kallsyms: increase maximum kernel symbol length to 512

[Petr Mladek]

On Thu 2022-05-05 21:16:45, Miguel Ojeda wrote:
> Rust symbols can become quite long due to namespacing introduced
> by modules, types, traits, generics, etc. For instance,
> the following code:
> 
>     pub mod my_module {
>         pub struct MyType;
>         pub struct MyGenericType<T>(T);
> 
>         pub trait MyTrait {
>             fn my_method() -> u32;
>         }
> 
>         impl MyTrait for MyGenericType<MyType> {
>             fn my_method() -> u32 {
>                 42
>             }
>         }
>     }
> 
> generates a symbol of length 96 when using the upcoming v0 mangling scheme:
> 
>     _RNvXNtCshGpAVYOtgW1_7example9my_moduleINtB2_13MyGenericTypeNtB2_6MyTypeENtB2_7MyTrait9my_method
> 
> At the moment, Rust symbols may reach up to 300 in length.
> Setting 512 as the maximum seems like a reasonable choice to
> keep some headroom.
> 
> Co-developed-by: Alex Gaynor <alex.gaynor@xxxxxxxxx>
> Signed-off-by: Alex Gaynor <alex.gaynor@xxxxxxxxx>
> Co-developed-by: Wedson Almeida Filho <wedsonaf@xxxxxxxxxx>
> Signed-off-by: Wedson Almeida Filho <wedsonaf@xxxxxxxxxx>
> Co-developed-by: Gary Guo <gary@xxxxxxxxxxx>
> Signed-off-by: Gary Guo <gary@xxxxxxxxxxx>
> Co-developed-by: Boqun Feng <boqun.feng@xxxxxxxxx>
> Signed-off-by: Boqun Feng <boqun.feng@xxxxxxxxx>
> Signed-off-by: Miguel Ojeda <ojeda@xxxxxxxxxx>

I was primary interested into the livepatching code.
But the entire patch looks good:

Reviewed-by: Petr Mladek <pmladek@xxxxxxxx>

I just hope that it will not cause stack overflows
somewhere.

Best Regards,
Petr