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
Subject: Re: kern/42228: Kernel deadlock prevents further file system access
Date: Sun, 25 Oct 2009 14:50:25 +0100

 On Sun, Oct 25, 2009 at 12:10:01PM +0000, tron%zhadum.org.uk@localhost wrote:
 > >Description:
 > My NetBSD/amd64 5.0/5.0_STABLE server has locked up at multiple occasions.
 > The symptoms are always identical:
 > 1.) The system still responds to ICMP Echo packets.
 > 2.) Services that don't access the file system (frequently) like e.g.
 >     BIND still work.
 > 3.) Any other processes (Postfix, Apache, inetd, etc.) are stuck.
 > I have to recover the machine by dropping into "ddb" and using "sync"
 > or "reboot" to force a restart.
 > 
 > The system managed to write a crash dump (to "raid0b" in case it
 > matters) after several of the crashes but "savecore" always claims
 > there is no crash dump once the system is back up. The only debug
 > information I therefore have is the stack trace of multiple of
 > the hung process after the latest incident. The stack traces all
 > look like this:
 > 
 > sleepq_block
 > turnstile_block
 > rw_vector_enter
 > vlockmgr
 > VOP_LOCK
 > vn_lock
 > namei
 > 
 > 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.
 
 -- 
 Manuel Bouyer <bouyer%antioche.eu.org@localhost>
      NetBSD: 26 ans d'experience feront toujours la difference
 --