svn commit: r309891 - head/sys/kern

[Edward Tomasz Napierala]

On 1212T1833, Konstantin Belousov wrote:
> On Mon, Dec 12, 2016 at 03:22:22PM +0000, Edward Tomasz Napierala wrote:
> > Author: trasz
> > Date: Mon Dec 12 15:22:21 2016
> > New Revision: 309891
> > URL: https://svnweb.freebsd.org/changeset/base/309891
> > 
> > Log:
> >   Avoid dereferencing NULL pointers in devtoname().  I've seen it panic,
> >   called from ufs_print() in DDB.
> Calls from DDB should not panic even if accessing NULL pointers.

Yeah, by "panic" I've meant the "reentering ddb" thing.  It's not a panic
per se, but still breaks eg "show lockedvnodes".

> That said, I also do not think that this is the right place to change.
> UFS um_dev should not be NULL for any active mount.

After looking at this once again I agree.  Looks like some kind of bug
specific to my sources at that point of time.  Backed off.