HEADS UP: KBI breakage for Ethernet modules

Scott Long scottl at samsco.org
Tue May 29 15:20:44 UTC 2007

Yar Tikhiy wrote:
> On Sun, May 27, 2007 at 03:51:29PM +0400, Yar Tikhiy wrote:
>> As discussed earlier on -net, I'd like to commit the following
>> patch.  It will bring ether_ioctl() into accord with ioctl() WRT
>> the type of the command argument.  In our ioctl(), command became
>> an u_long ages ago, but ether_ioctl() has never been fixed.  With
>> int and u_long being of different widths on 64-bit arch'es, the
>> discrepancy can get us in trouble sooner or later.
>> In fact, ioctl command coding is very unlikely to change, so it
>> will continue to fit in 32 bits.  OTOH, the C compiler should be
>> uneasy about squeezing u_long into int when ether_ioctl() is called
>> from an if_ioctl handler, so this patch will be a little step on
>> the way to a warning-free kernel.
>> This change will inevitably break the kernel interface to network
>> modules, so all of them will need rebuilding.
> I received several positive replies and no negative ones, so the
> change has just been committed.  In fact, it breaks KBI on 64-bit
> platforms only.  (Thanks to Ruslan Ermilov for reminding me about
> that.)  Many thanks to those folks who encouraged the change.
> Now all Ethernet-related kernel modules need to be rebuilt on 64-bit
> platforms.  The conventional "make buildkernel" procedure will take
> care of stock modules, so only 3rd-party modules need some attention.

How does this affect 32-bit compatibility on amd64?


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