Date: Mon, 14 Jun 1999 21:21:43 -0700 (PDT) From: Matthew Dillon <dillon@apollo.backplane.com> To: "David E. Cross" <crossd@cs.rpi.edu>, David Scheidt <dscheidt@enteract.com>, Chan Yiu Wah <c5666305@hkstar.com>, freebsd-current@FreeBSD.ORG Subject: NFS vnode reference issues on server Message-ID: <199906150421.VAA14439@apollo.backplane.com>
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:> Ack, you may have opened up a can of worms here. I don't even think
:> that nfs_namei() does the right thing when it returns an error... it
:> doesn't look like it clears the ndp->ni_vp either in some error cases.
:>
:> We are going to have to instrument the code - basically means NULLing
:> out ni_vp and any local vnode pointer when the vnode in question is
:> released so we can keep track of it and putting KASSERT()s in strategic
:> places. nfs_namei() in nfs/nfs_subs.c and just about all the subroutines
:> defined in nfs/nfs_serv.c.
:
:OK, you hijacked my thread ... OK, I've done worse, but please, could
:you change the subject line? We *do* still have a ctm outage here, it's
:clearing up (I hope) but I want feedback, and you've prevented it.
Oops, didn't even notice. Fixed.
Ok, something for people following the code to look over if they have
the time. This in nfs_subs.c, nfs_namei(). Question: ndp->ni_vp
is non-NULL and appears to be referenced as of the time a badlink
occurs, linklen is 0, or the link is too long. Do we have to
release ndp->ni_vp and NULL it out in this case? I believe so.
nfs_namei(...) {
...
if (error) {
badlink:
>>>>>>>>>> release/NULL ndp->ni_vp ??? <<<<<<<<<
if (ndp->ni_pathlen > 1)
zfree(namei_zone, cp);
break;
}
linklen = MAXPATHLEN - auio.uio_resid;
if (linklen == 0) {
error = ENOENT;
goto badlink;
}
if (linklen + ndp->ni_pathlen >= MAXPATHLEN) {
error = ENAMETOOLONG;
goto badlink;
}
-Matt
Matthew Dillon
<dillon@backplane.com>
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