Re: sysinstall spec_getpages panic (with VM overtones)

At Wed, 20 Aug 2003 17:31:39 -0400 (EDT),
Robert Watson wrote:
> > *c0529513 = "/usr/src/sys/fs/specfs/spec_vnops.c", line 0x300 is line 768:
> > 
> > 766     gotreqpage = 0;
> > 767     VM_OBJECT_LOCK(vp->v_object);
> > 768     vm_page_lock_queues();
> > 769     for (i = 0, toff = 0; i < pcount; i++, toff = nextoff) {
> > 
> > so ap->a_vp is null. I'#m afraid that's the limit of my ddb ability. 
> > 
> > Any suggestions as to where I should go from here? I don't really have
> > the facility at the moment to make release to test patches but will try
> > to if necessary. 
> 
> Is it ap->a_vp that's NULL, or vp->v_object that's NULL?  vp is
> dereferenced several times before that in the code, so if vp is really
> NULL at line 767, we're probably talking about memory corruption.  But if
> vp->v_object is NULL, then it could be we're not creating a VM object
> along some code path.

FWIW, ffs_getpages() at ffs_vnops.c:938, dp->v_object is NULL.  Where
this should be allocated?


-- 
Jun Kuriyama <kuriyama_at_imgsrc.co.jp> // IMG SRC, Inc.
             <kuriyama_at_FreeBSD.org> // FreeBSD Project