Hi Pat, I found similar steps with ntfs-3g: On the server side: # Create volume and a file dd if=/dev/zero of=ntfs-volume bs=1024 count=$((10*1024)) mkfs.ntfs -F ntfs-volume mkdir /mnt/ntfs ntfs-3g ntfs-volume /mnt/ntfs echo foo > /mnt/ntfs/foo # Remount umount /mnt/ntfs ntfs-3g ntfs-volume /mnt/ntfs # Export echo '/mnt/ntfs *(fsid=1)' > /etc/exports exportfs -a On the client side mkdir /mnt/nfs mount <SERVER>:/mnt/ntfs /mnt/nfs find /mnt/nfs -exec cat {} \; # <-- Server crashes Cheers, Jakob On 11/11/14 16:36, Jakob Blomer wrote: > Hi Pat, > > thanks for the quick reply! I just created a bugzilla account. > > The best I can provide quickly uses the cvmfs file system, which is not > in the standard repositories but it is a normal fuse module. > > On the NFS server side: > o) Install cvmfs: > yum install > https://ecsft.cern.ch/dist/cvmfs/cvmfs-release/cvmfs-release-2-4.el6.noarch.rpm > yum install cvmfs > > o) Configure and mount cvmfs > echo 'CVMFS_HTTP_PROXY=DIRECT' > /etc/cvmfs/default.local > echo 'CVMFS_NFS_SOURCE=yes' >> /etc/cvmfs/default.local > mkdir /mnt/cvmfs > mount -t cvmfs grid.cern.ch /mnt/cvmfs > > o) Export via NFS > echo '/mnt/cvmfs *(ro,fsid=1)' > /etc/exports > exportfs -ra > > > On the NFS client side: > mkdir /mnt/nfs > mount <SERVER>:/mnt/cvmfs /mnt/nfs > ls /mnt/nfs # Server crashes > > > Let me see if I can produce something similar with a fuse module that > comes in the normal repository. > > Cheers, > Jakob > > > On 11/11/14 15:23, Pat Riehecky wrote: >> On 11/11/2014 07:50 AM, Jakob Blomer wrote: >>> Dear Scientific Linux team, >>> >>> the latest kernel 2.6.32-504 crashes if a fuse file system is accessed >>> from within the kernel space. As discovered by Simon, this happens for >>> instance when a fuse file system is re-exported via NFS. When it >>> happens, the stack trace starts with >>> >>> BUG: unable to handle kernel NULL pointer dereference at 0000000000000030 >>> IP: [<ffffffffa0202260>] fuse_dentry_revalidate+0xf0/0x400 [fuse] >>> >>> >>> The behavior was not present with the previous kernel 2.6.32-431.29.2. >>> Besides security patches, the latest kernel seems to also backport new >>> fuse features which triggers the problem. As a workaround, we managed >>> to avoid the problem with a small kernel patch [1]. >>> >>> Could you report the problem back to Redhat? If necessary, I can >>> provide detailed steps how to reproduce it. >>> >>> Cheers, >>> Jakob >>> >>> >>> [1] >>> https://raw.githubusercontent.com/cvmfs/aufs2-standalone/aufs2.1-32-rhel6.6/rhel6.6-fuse.patch >>> >> >> If we can get some more detailed replication steps it should help get >> the issue clearly explained to upstream. >> >> Do you have a bugzilla account? >> >> Pat >>