Re: kern/46221: Kernel panic in NFS server code

["J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost>]

The following reply was made to PR kern/46221; it has been noted by GNATS.

From: "J. Hannken-Illjes" <hannken%eis.cs.tu-bs.de@localhost>
To: Matthias Scheler <tron%zhadum.org.uk@localhost>
Cc: 
Subject: Re: kern/46221: Kernel panic in NFS server code
Date: Wed, 21 Mar 2012 15:44:28 +0100

 <snip>
 > 
 > Manual Bouyer has looked at this crash. The kernel paniced here:
 > 
 >         ip = VTOI(nvp);
 > -->     if (ip->i_mode == 0 || ip->i_gen != ufhp->ufid_gen) {
 >                 vput(nvp);
 >                 *vpp = NULLVP;
 >                 return (ESTALE);
 >         }
 > 
 > I guess that an extra check whether "ip" is NULL would prevent the
 > panic. But I'm not sure whether that is the correct fix.
 
 Please change this to
 
        ip = VTOI(nvp);
 +      if (ip == NULL) {
 +              vprintf("NULL IP", nvp);
 +              panic("NULL IP");
 +      }
        if (...
 
 so on the next crash we know more about the state of the vnode/inode.
 
 If you are able to debug the core dump you could `print *nvp' here.
 
 --
 Juergen Hannken-Illjes - hannken%eis.cs.tu-bs.de@localhost - TU Braunschweig 
(Germany)