Re: Kernel panics with vfs.nfsd.enable_locallocks=1 and nfs clients doing hdf5 file operations

Hi Rick,

Done - https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=280978

Thanks!

-Matt

On 8/21/24 10:45 AM, Rick Macklem wrote:
> Please create a PR for this and include at least
> one backtrace. I will try and figure out how
> locallocks could cause it.
> 
> I suspect few use locallocks=1.
> 
> rick
> 
> On Wed, Aug 21, 2024 at 7:29 AM Matthew L. Dailey 
> <Matthew.L.Dailey@dartmouth.edu <mailto:Matthew.L.Dailey@dartmouth.edu>> 
> wrote:
> 
>     Hi all,
> 
>     I posted messages to the this list back in February and March
>     (https://lists.freebsd.org/archives/freebsd-current/2024-February/005546.html <https://lists.freebsd.org/archives/freebsd-current/2024-February/005546.html>)
>     regarding kernel panics we were having with nfs clients doing hdf5 file
>     operations. After a hiatus in troubleshooting, I had more time this
>     summer and have found the cause - the vfs.nfsd.enable_locallocks sysctl.
> 
>     When this is set to 1, we can induce either a panic or hung nfs server
>     (more rarely) usually within a few hours, but sometimes within several
>     days to a week. We have replicated this on 13.0 through 15.0-CURRENT
>     (20240725-82283cad12a4-271360). With this set to 0 (default), we are
>     unable to replicate the issue, even after several weeks of 24/7 hdf5
>     file operations.
> 
>     One other side-effect of these panics is that on a few occasions it has
>     corrupted the root zpool beyond repair. This makes sense since kernel
>     memory is getting corrupted, but obviously makes this issue more
>     impactful.
> 
>     I'm hoping this is enough information to start narrowing down this
>     issue. We are specifically using this sysctl because we are also
>     serving
>     files via samba and want to ensure consistent locking.
> 
>     I have provided some core dumps and backtraces previously, but am happy
>     to provide more as needed. I also have a writeup of exactly how to
>     reproduce this that I can send directly to anyone who is interested.
> 
>     Thanks so much for any and all help with this tricky problem. I'm happy
>     to do whatever I can to help get this squashed.
> 
>     Best,
>     Matt
>