Kernel failure while writing DVD-RAM

[Dave Higton]

I'm testing DVD-RAM writing and reading for reliability under Fedoras 10
and 5.  While writing some files under F10 this afternoon, there was a
kernel failure.  Details below:

WARNING: at fs/buffer.c:1186 mark_buffer_dirty+0x27/0x79() (Not tainted)
Hardware name: OptiPlex 755                 
Modules linked in: udf crc_itu_t fuse i915 drm bridge stp bnep sco l2cap
bluetooth sunrpc nf_conntrack_netbios_ns nf_conntrack_ftp ip6t_REJECT
nf_conntrack_ipv6 ip6table_filter ip6_tables ipv6 cpufreq_ondemand
acpi_cpufreq dm_multipath uinput snd_hda_intel snd_seq_dummy snd_seq_oss
snd_seq_midi_event snd_seq snd_seq_device snd_pcm_oss snd_mixer_oss
snd_pcm snd_timer snd_page_alloc snd_hwdep ata_generic i2c_i801 snd
ppdev i2c_core iTCO_wdt iTCO_vendor_support parport_pc pata_acpi
serio_raw dcdbas soundcore pcspkr parport e1000e e1000 joydev [last
unloaded: microcode]
Pid: 12876, comm: fillDVD2 Not tainted 2.6.27.37-170.2.104.fc10.i686 #1
 [<c042ddfb>] warn_on_slowpath+0x65/0x8b
 [<c04228dc>] ? __enqueue_entity+0xe3/0xeb
 [<c0424346>] ? enqueue_entity+0x203/0x20b
 [<c06abe09>] ? _spin_lock+0x8/0xb
 [<c0495510>] ? inode_sub_bytes+0x69/0x71
 [<c04afeef>] mark_buffer_dirty+0x27/0x79
 [<f8ea4cb3>] udf_bitmap_free_blocks+0xf8/0x12e [udf]
 [<f8ea51ba>] udf_free_blocks+0x62/0x8c [udf]
 [<f8eae3f1>] extent_trunc+0xe5/0xf0 [udf]
 [<f8eae88a>] udf_discard_prealloc+0xce/0x17b [udf]
 [<f8ea5844>] udf_release_file+0x18/0x22 [udf]
 [<c04939ad>] __fput+0xad/0x13d
 [<c0493a54>] fput+0x17/0x19
 [<c04912e7>] filp_close+0x50/0x5a
 [<c0491363>] sys_close+0x72/0xb1
 [<c0404c8a>] syscall_call+0x7/0xb
 =======================
---[ end trace d4c5a1d53380a8a7 ]---

This is a standard installation from a Fedora 10 DVD, whose image was
taken from the web.

Other than "yup, it's broken", does the above trace mean anything to
anyone, and is there anything I can do to make it work reliably or even
to diagnose it further?

fillDVD2 is my app, written in C, which simply writes sequential files
of 1 MB each to the DVD on /dev/sr0.  I can post the source if anyone
wants to see it.

Looking further ahead, the aim was to try to fix writing DVD-RAM under
Fedora 5.  We know this is broken, and I was hoping to back-port the F10
code to F5.  Up to now, we had only observed failures under F5, never
F10 - this is the first.  The failures were entirely different: F5 would
occasionally fail to write beyond 4 GB, and would consistently write
DVD-RAMs that showed allocation errors when examined by the Philips
udf_test application.  F10 has never exhibited either of those failures.
F5 has never shown an oops.  Now it seems I can no longer rely on the
F10 UDF code either.

Dave