Most recent kernel where this bug did not occur: 2.6.22
Distribution: - (opensuse based)
Hardware Environment: pc, amd64x2, dvd writer
Software Environment: shell, x86_64 and i686 kernels
Problem Description:
When I try to setup packet writing on any ide block device using the sysfs interface, I get a segfault and dmesg shows a message about a kernel bug in pkt_setup_dev+0x476/0x480 [pktcdvd].

Steps to reproduce:

modprobe pktcdvd
echo 22:0 >/sys/class/pktcdvd/add


Message from dmesg (using i686 kernel):

------------[ cut here ]------------
Kernel BUG at f8ef7bf6 [verbose debug info unavailable]
invalid opcode: 0000 [#1]
SMP
Modules linked in: pktcdvd udf cls_fw ipt_REJECT xt_limit xt_state xt_TCPMSS xt_tcpudp iptable_filter ipt_MASQUERADE iptable_nat nf_conntrack_ipv4 ip_tables nf_nat_ftp nf_nat nf_conntrack_ftp nf_conntrack ipt_LOG x_tables sch_htb sis900 bitrev crc32 nfsd exportfs lockd auth_rpcgss sunrpc snd_pcm_oss snd_seq_oss snd_mixer_oss snd_seq_midi snd_seq_midi_event snd_seq snd_ens1371 snd_ac97_codec ac97_bus snd_usb_audio snd_pcm snd_timer snd_page_alloc snd_usb_lib snd_rawmidi snd_seq_device snd_hwdep ehci_hcd ohci_hcd forcedeth dummy k8temp w83627ehf hwmon_vid usb_storage aes_i586 dm_crypt dm_mod loop tuner tvaudio bttv video_buf firmware_class ir_common compat_ioctl32 i2c_algo_bit btcx_risc tveeprom i2c_core videodev v4l1_compat v4l2_common usblp ppdev parport_pc lp parport pppoe pppox ppp_generic slhc usbhid floppy ide_cd cdrom cpufreq_ondemand cpufreq_performance cpufreq_powersave rtc
CPU:    0
EIP:    0060:[<f8ef7bf6>]    Not tainted VLI
EFLAGS: 00210246   (2.6.23 #1)
EIP is at pkt_setup_dev+0x476/0x480 [pktcdvd]
eax: 00000000   ebx: 01600040   ecx: c23820c4   edx: f8efdd80
esi: f5613880   edi: 00000000   ebp: f64cf200   esp: f4b5decc
ds: 007b   es: 007b   fs: 00d8  gs: 0033  ss: 0068
Process pktcdvd (pid: 4290, ti=f4b5c000 task=f49ceab0 task.ti=f4b5c000)
Stack: f5613888 f8ef9ee8 00000000 f4b5df08 f4b5df38 f4b5df38 00000000 f5613888
       00000000 f6fa1040 f4b5df38 f54d9000 00000002 ffffffff f8ef9f23 f54d9005
       00000006 f534a418 00000006 f534a418 f54d9000 00000006 f8ef7c49 f54d9000
Call Trace:
 [<f8ef7c49>] class_pktcdvd_store_add+0x49/0x60 [pktcdvd]
 [<f8ef7c00>] class_pktcdvd_store_add+0x0/0x60 [pktcdvd]
 [<c0310e79>] class_attr_store+0x29/0x40
 [<c01a9d2a>] sysfs_write_file+0xda/0x120
 [<c01a9c50>] sysfs_write_file+0x0/0x120
 [<c016e8bf>] vfs_write+0xbf/0x140
 [<c016ef41>] sys_write+0x41/0x70
 [<c010426e>] sysenter_past_esp+0x5f/0x85
 =======================
Code: 04 24 d4 a2 ef f8 e8 ca fa 22 c7 8b 44 24 24 e8 21 b6 29 c7 b8 80 dd ef f8 e8 77 08 25 c7 c7 44 24 20 f4 ff ff ff e9 7a fd ff ff <0f> 0b eb fe 8d b6 00 00 00 00 53 89 cb 83 ec 18 8d 44 24 10 89
EIP: [<f8ef7bf6>] pkt_setup_dev+0x476/0x480 [pktcdvd] SS:ESP 0068:f4b5decc