Re: kern/48411: repeatable SMP crashes in amd64-current

[David Holland <dholland-bugs%netbsd.org@localhost>]

The following reply was made to PR kern/48411; it has been noted by GNATS.

From: David Holland <dholland-bugs%netbsd.org@localhost>
To: gnats-bugs%netbsd.org@localhost
Cc: 
Subject: Re: kern/48411: repeatable SMP crashes in amd64-current
Date: Thu, 28 Nov 2013 05:42:24 +0000

 On Thu, Nov 28, 2013 at 05:15:00AM +0000, David Holland wrote:
  >  On Thu, Nov 28, 2013 at 01:05:00AM +0000, Hisashi T Fujinaka wrote:
  >   >  rmind suggested I check
  >   >  http://mail-index.netbsd.org/source-changes/2013/11/23/msg049417.html
  >   >  where hannken changed src/sys/kern/vfs_vnode.c src/sys/sys/vnode.h
  >   >  
  >   >                  cvs rdiff -u -r1.25 -r1.26 src/sys/kern/vfs_vnode.c
  >   >                  cvs rdiff -u -r1.240 -r1.241 src/sys/sys/vnode.h
  >   >  
  >   >  Reverting this change fixes my hangs so far. Before I couldn't complete
  >   >  a build of netbsd, now I can build netbsd and pkgsrc simultaneously.
  >  
  >  alas... that patch really did look like a step forward.
  >  
  >  Did you ever get a clear trace of the deadlock?
 
 after some discussion in chat and looking at the url cited in the PR,
 it looks like (1) layerfs is definitely involved, and (2) deep
 suspicion attaches to layer_node_find().
 
 see http://www.i8u.org/~htodd/crash/6b00.jpg and note that in the
 initial ps output, the lwp that isn't tstiling is waiting on "layerfs".
 
 -- 
 David A. Holland
 dholland%netbsd.org@localhost