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Date: Wed, 26 Apr 2023 13:38:32 +0200
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Subject: Re: Link modules to DYN type
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To: Konstantin Belousov <kostikbel@gmail.com>
Cc: Zhenlei Huang <zlei@freebsd.org>,
 FreeBSD CURRENT <freebsd-current@freebsd.org>,
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On 4/26/23 13:12, Konstantin Belousov wrote:
> No, in-kernel linker does not behave this way.
> Modules need to contain explicit reference to all modules they depend upon,
> using the MODULE_DEPEND() macro.  Only symbols from the dependencies are
> resolved.
> 
> All modules get an implicit reference to kernel.

Hi Konstantin,

Maybe I wasn't so clear. Trying again:

> diff --git a/sys/tests/ktest.c b/sys/tests/ktest.c
> index 495fedf95dde..eb42cf062487 100644
> --- a/sys/tests/ktest.c
> +++ b/sys/tests/ktest.c
> @@ -409,6 +409,12 @@ static moduledata_t ktestmod = {
>          0
>  };
>  
> +int
> +printf(const char *fmt, ...)
> +{
> +       return (0);
> +}
> +
>  DECLARE_MODULE(ktestmod, ktestmod, SI_SUB_PSEUDO, SI_ORDER_ANY);
>  MODULE_VERSION(ktestmod, 1);
>  MODULE_DEPEND(ktestmod, netlink, 1, 1, 1);

Then kldload ktest.ko . Which printf() function will be used if ktest.c 
calls printf() ?

I would expect a warning from the kernel at least ...

--HPS