Without fail, writing any kind of level 0 dump to /dev/nht0 hangs the system after a while under RedHat 6.0. This includes tar and dump directly to /dev/nht0 or piped through to dd. I suspect ide-tape.c. We're running RedHat Linux with the 2.2.5-22smp SMP kernel writing to a Seagate STT28000A-RF ATAPI Travan-4 tape drive. Backups worked under RedHat 5.2, since I made them in preparation for full, fresh installs of RedHat 6.0. I have seen many, many reports of this problem with IDE tape drives. Gadi Oxman, the author of ide-tape.c, suggested in reply to one such problem a patch to take ide-tape.c from version 1.14 to 1.15, but the patch fails on several hunks.
Gadi Oxman, the maintainer of /usr/src/linux/drivers/block/ide-tape.c, sent a patch to upgrade it from version 1.14 to 1.15. That patch installed flawlessly on RedHat's kernel version 2.2.5-22. I was then able to do a tar backup of all our file systems, which include a pair of 1.37 gigabyte seismic data files. According to Gadi, his patch resolves some problem between ide-tape.c and the SMP, which we are using in our kernel.
Can you post the patch?
We should ask Gadi for the patch if the next kernel we release does not have the new ide-tape driver in it, or get it ourselves if it is otherwise available. Newer 2.2.x kernels might include the newer driver; I have not checked yet. We should certainly use a new ide-tape driver anyway because of the bug that slab poisoning found; I don't know if this is that same bug or another bug.
fixed in the latest kernels in Raw Hide.