mb alloc and: panic: mutex Giant not owned at ../../../vm/vm_kern.c:315

[Andrew Gallatin]

David Malone writes:
 > > > This may be my fault, as I made some changes recently that assumed that
 > > > the mbuf allocator grabbed giant when needed. I'll check the code path
 > > > you've mentioned to see if it grabs giant now, but I suspect that I just
 > > > need to move the giant grabbing back where it was before. 
 > 
 > > This doesn't seem to be a reproduceable problem for me, FWIW, (presumably
 > > a property of bucket sizes, etc) so you have all the information I have
 > > :-).
 > 
 > You'd have to be quite unlucky to trigger it (calling sendit at a
 > time when a per-cpu mbuf pool was empty). I have a vague feeling
 > that my sendit change isn't the only place that does this.

FWIW, calling kmem_malloc() w/o Giant is safe if you call with
NOWAIT.  But if you wait, you must hold Giant.

Drew