Re: kern/42228: Kernel deadlock prevents further file system access

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

The following reply was made to PR kern/42228; it has been noted by GNATS.

From: Manuel Bouyer <bouyer%antioche.eu.org@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: kern-bug-people%NetBSD.org@localhost, gnats-admin%NetBSD.org@localhost, 
netbsd-bugs%NetBSD.org@localhost,
        tron%zhadum.org.uk@localhost
Subject: Re: kern/42228: Kernel deadlock prevents further file system access
Date: Sun, 25 Oct 2009 15:15:07 +0100

 On Sun, Oct 25, 2009 at 02:05:03PM +0000, Matthias Scheler wrote:
 >  >  > The function after "namei" differs from case to case. Examples are
 >  >  > vn_open() or do_sys_stat().
 >  >  
 >  >  this looks a lot like the ffs VOP_RENAME race issue.
 >  
 >  Is there a patch available which I can try out?
 
 A first try has been posted to tech-kern but unfortunably it's buggy
 (and makes things worse, we now have "looking against myself" panics).
 
 > And I don't understand
 >  why that would happen frequently on one of my 24/7 NetBSD 5.0_STABLE
 >  systems but not on the other, they both use FFS. Is it e.g. more likely
 >  to happen on systems with multiple CPU cores?
 
 Yes, multiple CPUs will make things worse, as does using WAPBL
 (WAPBL is unusable for me on systems using rsync for example).
 
 -- 
 Manuel Bouyer <bouyer%antioche.eu.org@localhost>
      NetBSD: 26 ans d'experience feront toujours la difference
 --