[OpenAFS-devel] BUG: unable to handle kernel NULL pointer

[Markus Suvanto]

Kernel 3.9.2 and openafs 1.6.3pre2

 489.338107] BUG: unable to handle kernel NULL pointer dereference at
         (null)
[  489.338490] IP: [<          (null)>]           (null)
[  489.338692] PGD 37b9b067 PUD 37a0c067 PMD 0
[  489.339009] Oops: 0010 [#1] SMP
....

Easy way to reproduce this:  use tmpfs as openafs cache and try to
compile kernel
git clone /path/to/kernel
cd kernel
make oldconfig
make -j16

For example my fstab
tmpfs            /var/cache/openafs    tmpfs    size=1g            0 0

Also  using  btrfs will hang (I have not tested ext4/ext3), but it
will take longer to reproduce.
/dev/vda3        /var/cache/openafs    btrfs
noatime,,subvol=openafs_cache    0 0

Also memcache eventually hang but some times it take days to hit this.

Note that this test case is running under KVM virtual machine, but
real HW hangs also.
This is gentoo, gcc (Gentoo 4.6.3 p1.13, pie-0.5.2) 4.6.3

-Markus