Re: [PATCH] modpost: check for NULL filename pointer in find_module()

[Masahiro Yamada]

On Mon, Jul 7, 2025 at 6:09 AM Siddharth Nayyar <sidnayyar@xxxxxxxxxx> wrote:
>
> Pointer for dump filename can be NULL when a module is not created from
> a dump file in modpost. The find_module() function should therefore
> check whether the dump filename pointers are NULL before comparing them
> using strcmp().

I do not understand.
I do not think that scenario would happen.

There are two call-sites for new_module():
[1] https://github.com/torvalds/linux/blob/v6.15/scripts/mod/modpost.c#L1576
[2] https://github.com/torvalds/linux/blob/v6.15/scripts/mod/modpost.c#L2117


For [2], mod->dump_file is set in the next line.

[1] is always called after read_dump(), where
is the only user of find_module(). [3]

[3]: https://github.com/torvalds/linux/blob/v6.15/scripts/mod/modpost.c#L2115






> Signed-off-by: Siddharth Nayyar <sidnayyar@xxxxxxxxxx>
> ---
>  scripts/mod/modpost.c | 8 ++++++--
>  1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/scripts/mod/modpost.c b/scripts/mod/modpost.c
> index 5ca7c268294e..9a64d0a55f89 100644
> --- a/scripts/mod/modpost.c
> +++ b/scripts/mod/modpost.c
> @@ -178,8 +178,12 @@ static struct module *find_module(const char *filename, const char *modname)
>         struct module *mod;
>
>         list_for_each_entry(mod, &modules, list) {
> -               if (!strcmp(mod->dump_file, filename) &&
> -                   !strcmp(mod->name, modname))
> +               if (strcmp(mod->name, modname) != 0)
> +                       continue;
> +               if (!mod->dump_file && !filename)
> +                       return mod;
> +               if (mod->dump_file && filename &&
> +                   !strcmp(mod->dump_file, filename))
>                         return mod;
>         }
>         return NULL;
> --
> 2.50.0.727.gbf7dc18ff4-goog
>


-- 
Best Regards
Masahiro Yamada