Re: Ioctl warning for a partition

[Michael Tokarev <mjt@tls.msk.ru>]

On 27.01.2012 03:01, Linus Torvalds wrote:
> On Thu, Jan 26, 2012 at 2:30 PM, Jan Kara <jack@suse.cz> wrote:
>>
>> It's easy enough to silence the warning the same way as
>> CDROM_GET_CAPABILITY since the ioctl is safe but it's not so simple for
>> 32-bit userspace.  MTIOCGET32 is defined only in fs/compat_ioctl.c so we
>> cannot easily add it to scsi_verify_blk_ioctl(). Any opinion how to cleanly
>> solve this? The only idea I had was to define compat structures and ioctl
>> numbers in a special header and use it both in fs/compat_ioctl.c and in
>> block/scsi_ioctl.c.
> 
> I suspect we can just remove the warning entirely - once we've gotten
> enough coverage with the -rc kernels that people (me in particular)
> are happy that no normal load really needs it, and returning an error
> is fine.
> 
> So I don't really consider the warning to be something long-term - I
> wanted it to make sure that some random binary in some odd
> distribution wouldn't break in mysterious ways that would take a lot
> of debugging to find. And so that we really know what we end up
> blocking in practice.
> 
> I'm not sure how good the -rc kernel coverage is, but I think it's
> good enough that we can drop the warning before doing a real 3.3
> release. And I don't think the stable kernel versions ever got that
> warning printout, did they? That would be great for coverage, of
> course, if they did.

They did, 3.0 and 3.2.

For example, 3.0.18:

[  610.488489] kvm: sending ioctl 5326 to a partition!
[  610.488540] kvm: sending ioctl 80200204 to a partition!

mdadm ioctls reported in various places apparently got fixed by
ENOTTY/ENOIOCTLCMD change.

Thanks,

/mjt