Re: kern/53096 (netbsd-8 crash on heavy disk I/O)

[Roy Bixler <rcbixler%nyx.net@localhost>]

On Mon, Apr 02, 2018 at 03:55:01PM +0000, Roy Bixler wrote:
> The following reply was made to PR kern/53096; it has been noted by GNATS.
> 
> From: Roy Bixler <rcbixler%nyx.net@localhost>
> To: gnats-bugs%NetBSD.org@localhost
> Cc: 
> Subject: Re: kern/53096 (netbsd-8 crash on heavy disk I/O)
> Date: Mon, 2 Apr 2018 09:47:56 -0600
> 
>  On Tue, Mar 20, 2018 at 05:34:34PM +0000, jdolecek%NetBSD.org@localhost wrote:
>  > Synopsis: netbsd-8 crash on heavy disk I/O
>  > 
>  > State-Changed-From-To: closed->open
>  > State-Changed-By: jdolecek%NetBSD.org@localhost
>  > State-Changed-When: Tue, 20 Mar 2018 17:34:34 +0000
>  > State-Changed-Why:
>  > hannken wants to investigate it more.
>  
>  Good call, as this seems to be a difficult-to-reproduce issue.  I
>  reverted to going to regular builds and I just had the same problem
>  today while trying to do a "cvs up" on pkgsrc to go from -2017Q4 to
>  2018Q1.  The kernel version is:
>  
>  NetBSD rbixler.britannica.net 8.0_BETA NetBSD 8.0_BETA (GENERIC.201803222040Z) amd64
>  
>  The backtrace from the crash dump was very similar.  I will try to
>  reproduce the problem with a gdb-enabled kernel as recommended by
>  hannken.

I compiled a GDB-enabled kernel and got a crash.  I'm not really sure
how to use GDB, but here's what I get from the "crash" command:.

# crash -M netbsd.3.core -N netbsd.3
Crash version 8.0_BETA, image version 8.0_BETA.
System panicked: kernel diagnostic assertion "vp->v_usecount != 0" failed: file "/usr/src/sys/kern/vfs_vnode.c", line 890
Backtrace from time of crash is available.

This is with netbsd-8 source updated from this morning and includes your
patch to "sys/kern/vfs_vnode.c".

-- 
Roy Bixler <rcbixler%nyx.net@localhost>
"The fundamental principle of science, the definition almost, is this: the
sole test of the validity of any idea is experiment."
-- Richard P. Feynman