Re: Missing symbol on sh4: "__get_user_unknown"

On 5/10/20 3:27 PM, Ben Hutchings wrote:
>> In any case, the kernel package now fails to build due to a missing symbol in the
>> Infiniband core driver (see below). A simple workaround is to disable Infiniband
>> support which allows me to build the kernel package normally (which I did and
>> consequently uploaded).
> [...]
> 
> __get_user_unknown() is never defined, but will be referenced if the
> get_user() macro is invoked with a variable of unsupported size (see
> arch/sh/include/asm/uaccess.h).  So my guess is that this module uses
> get_user() to read a 64-bit value.  Some 32-bit architectures do now
> support this operation but I'm not sure whether they are expected to.

I see, thanks a lot for the explanation.

> This seems to have been introduced by commit 3a6532c9af1a, and could
> probably be fixed by replacing the get_user() with a copy_from_user().
> 
> We could disable IB since it doesn't seem that likely to be used on
> sh4, although I think the "verbs" layer can be used on top of Ethernet.

I'm fine with that.

Adrian