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