Re: kern/42455: tstile hang with nfs

["Christoph Egger" <Christoph_Egger%gmx.de@localhost>]

The following reply was made to PR kern/42455; it has been noted by GNATS.

From: "Christoph Egger" <Christoph_Egger%gmx.de@localhost>
To: gnats-bugs%NetBSD.org@localhost, netbsd-bugs%netbsd.org@localhost, 
gnats-admin%netbsd.org@localhost,
 kern-bug-people%netbsd.org@localhost
Cc: 
Subject: Re: kern/42455: tstile hang with nfs
Date: Tue, 26 Oct 2010 11:53:49 +0200

 >  hi,
 >  
 >  >>  >  I added some more debug lines and figured out that the macro
 >  >>  >  nfsm_wcc_data() drops the mbuf chain w/o decreasing
 >  >>  >  ctxt.nwc_mbufcount.
 >  >>  
 >  >>  The nfsm_wcc_data() macro calls the nfsm_postop_attr() macro.
 >  >>  The nfsm_postop_attr() macro calls nfsm_loadattrcache() function.
 >  >>  The nfsm_loadattrcache() function calls nfsm_disct() function.
 >  >>  
 >  >>  nfsm_disct() is the function in error which drops the mbuf chain.
 >  
 >  are you sure?
 
 yes, absolutely and reproducable.
 
 >  iirc, nwc_mbufcount is about sending mbuf.  otoh, nfsm_disct
 >  is for received mbuf.
 
 nfs_writerpc *does* call nfsm_disct() through nfsm_wcc_data,
 nfsm_postop_attr and nfsm_loadattrcache in this order.
 
 So you are saying this should never happen?
 
 Christoph