Re: CVS commit: src/sys/kern

[Antti Kantee <pooka%cs.hut.fi@localhost>]

On Wed Nov 12 2008 at 18:22:06 +0100, Reinoud Zandijk wrote:
> Hiya Antti,
> 
> On Wed, Nov 12, 2008 at 03:59:32PM +0200, Antti Kantee wrote:
> > On Tue Nov 04 2008 at 16:08:41 +0000, Reinoud Zandijk wrote:
> > > 
> > > Module Name:      src
> > > Committed By:     reinoud
> > > Date:             Tue Nov  4 16:08:41 UTC 2008
> > > 
> > > Modified Files:
> > >   src/sys/kern: vfs_bio.c
> > > 
> > > Log Message:
> > > Don't dereference bp->b_vp->v_mount if its vnode type is VT_VNON. I dont
> > > know if this masks a bug but with a machine having a ffs+wapbl mount, NFS
> > > mounts and a ntfs mount this paniced the machine on suspend.
> > 
> > Where's the PR describing the actual problem?
> 
> There is no PR (yet); On suspend, all buffers on the bufhashtbl are 
> visited and if they are mounted with softdep an action is taken.
> 
> During this visit, a buffer came by that was NOT assigned to a particular 
> FS i.e. bp->b_vp->v_tag == VT_VNON. This buffer's bp->b_vp->v_mount was NOT 
> NULL though but rather typically 0x40 and so the bp->b_vp->v_mount check 
> failed. The kernel then dereferenced bp->b_vp->b_mount->mnt_flag to check 
> for the softdeps flag and it paniced.
> 
> The bug masking i am refering to that aparently in some cases 
> bp->b_vp->v_mount is not allways NULL or valid even though its v_tag is 
> VT_NON.

You wrote what you said the first time, but used 3x as many words now ;)

It would be interesting to see at least the buffer and vnode.