Latest working kernel version: Don't know?
Earliest failing kernel version: Don't know?
Distribution: Ubuntu Linux 8.04
Hardware Environment: AMD XP 2800+ ...
Software Environment: Don't know?
Problem Description:

I checked DMESG (this is while rebuilding a mdadm raid-5 array [expanding from 5 disks to 6], don't know if this is relevant?), and saw these lines:

[73712.181477] ------------[ cut here ]------------
[73712.181501] kernel BUG at /build/buildd/linux-2.6.24/fs/sysfs/file.c:126!
[73712.181519] invalid opcode: 0000 [#1] SMP 
[73712.181537] Modules linked in: nfsd lockd nfs_acl auth_rpcgss sunrpc exportfs cpufreq_powersave cpufreq_userspace cpufreq_ondemand cpufreq_conservative cpufreq_stats freq_table iptable_filter ip_tables x_tables reiserfs aes_i586 dm_crypt dm_mod asb100 hwmon_vid parport_pc lp af_packet parport loop ipv6 psmouse serio_raw button i2c_nforce2 nvidia_agp shpchp pci_hotplug i2c_core agpgart evdev pcspkr ext3 jbd mbcache sr_mod cdrom ata_generic sg sd_mod usbhid hid pata_amd sata_sil sata_promise pata_acpi skge libata scsi_mod ehci_hcd ohci_hcd forcedeth usbcore raid10 raid456 async_xor async_memcpy async_tx xor raid1 raid0 multipath linear md_mod thermal processor fan fbcon tileblit font bitblit softcursor fuse
[73712.181847] 
[73712.181859] Pid: 15130, comm: cat Not tainted (2.6.24-19-generic #1)
[73712.181876] EIP: 0060:[<c01d6ba8>] EFLAGS: 00010212 CPU: 0
[73712.181899] EIP is at sysfs_read_file+0xd8/0xe0
[73712.181914] EAX: 00000001 EBX: dc5fb900 ECX: 00000000 EDX: dfa7a5d0
[73712.181931] ESI: 00001000 EDI: dfa7a630 EBP: dc5fb914 ESP: f77dff54
[73712.181947]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[73712.181964] Process cat (pid: 15130, ti=f77de000 task=f1978000 task.ti=f77de000)
[73712.181981] Stack: b7f94ce0 00000000 00001000 08057000 f8892810 f7c9c404 f196e320 08057000 
[73712.182026]        c01d6ad0 00001000 c0192327 f77dffa0 00001000 f196e320 fffffff7 08057000 
[73712.182071]        f77de000 c0192881 f77dffa0 00000000 00000000 00000000 00000003 00001000 
[73712.182115] Call Trace:
[73712.182139]  [<c01d6ad0>] sysfs_read_file+0x0/0xe0
[73712.182160]  [<c0192327>] vfs_read+0xb7/0x170
[73712.182183]  [<c0192881>] sys_read+0x41/0x70
[73712.182203]  [<c01043c2>] sysenter_past_esp+0x6b/0xa9
[73712.182230]  =======================
[73712.182243] Code: 83 c4 18 5b 5e 5f 5d c3 be ed ff ff ff eb e8 b8 d0 00 00 00 be f4 ff ff ff e8 c5 c8 f9 ff 85 c0 89 43 0c 0f 85 6d ff ff ff eb cc <0f> 0b eb fe 8d 74 26 00 83 ec 14 89 74 24 08 8b 74 24 18 89 7c 
[73712.182430] EIP: [<c01d6ba8>] sysfs_read_file+0xd8/0xe0 SS:ESP 0068:f77dff54
[73712.182837] ---[ end trace 8a9fac7c77d2cf54 ]---

[73719.547003] ------------[ cut here ]------------
[73719.547071] kernel BUG at /build/buildd/linux-2.6.24/fs/sysfs/file.c:126!
[73719.547131] invalid opcode: 0000 [#2] SMP 
[73719.547278] Modules linked in: nfsd lockd nfs_acl auth_rpcgss sunrpc exportfs cpufreq_powersave cpufreq_userspace cpufreq_ondemand cpufreq_conservative cpufreq_stats freq_table iptable_filter ip_tables x_tables reiserfs aes_i586 dm_crypt dm_mod asb100 hwmon_vid parport_pc lp af_packet parport loop ipv6 psmouse serio_raw button i2c_nforce2 nvidia_agp shpchp pci_hotplug i2c_core agpgart evdev pcspkr ext3 jbd mbcache sr_mod cdrom ata_generic sg sd_mod usbhid hid pata_amd sata_sil sata_promise pata_acpi skge libata scsi_mod ehci_hcd ohci_hcd forcedeth usbcore raid10 raid456 async_xor async_memcpy async_tx xor raid1 raid0 multipath linear md_mod thermal processor fan fbcon tileblit font bitblit softcursor fuse
[73719.551066] 
[73719.551121] Pid: 15147, comm: cat Tainted: G      D (2.6.24-19-generic #1)
[73719.551182] EIP: 0060:[<c01d6ba8>] EFLAGS: 00010212 CPU: 0
[73719.551248] EIP is at sysfs_read_file+0xd8/0xe0
[73719.551306] EAX: 00000001 EBX: dc5fb780 ECX: 00000000 EDX: dfa7a5d0
[73719.551366] ESI: 00001000 EDI: dfa7a630 EBP: dc5fb794 ESP: dc4fdf54
[73719.551426]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[73719.551485] Process cat (pid: 15147, ti=dc4fc000 task=dd30cb80 task.ti=dc4fc000)
[73719.551545] Stack: b7fa2ce0 00000000 00001000 08057000 f8892810 f7c9c404 f1f07960 08057000 
[73719.552020]        c01d6ad0 00001000 c0192327 dc4fdfa0 00001000 f1f07960 fffffff7 08057000 
[73719.552494]        dc4fc000 c0192881 dc4fdfa0 00000000 00000000 00000000 00000003 00001000 
[73719.552968] Call Trace:
[73719.553078]  [<c01d6ad0>] sysfs_read_file+0x0/0xe0
[73719.553184]  [<c0192327>] vfs_read+0xb7/0x170
[73719.553293]  [<c0192881>] sys_read+0x41/0x70
[73719.553400]  [<c01043c2>] sysenter_past_esp+0x6b/0xa9
[73719.553514]  =======================
[73719.553569] Code: 83 c4 18 5b 5e 5f 5d c3 be ed ff ff ff eb e8 b8 d0 00 00 00 be f4 ff ff ff e8 c5 c8 f9 ff 85 c0 89 43 0c 0f 85 6d ff ff ff eb cc <0f> 0b eb fe 8d 74 26 00 83 ec 14 89 74 24 08 8b 74 24 18 89 7c 
[73719.556589] EIP: [<c01d6ba8>] sysfs_read_file+0xd8/0xe0 SS:ESP 0068:dc4fdf54
[73719.556767] ---[ end trace 8a9fac7c77d2cf54 ]---

[73757.369348] ------------[ cut here ]------------
[73757.369415] kernel BUG at /build/buildd/linux-2.6.24/fs/sysfs/file.c:126!
[73757.369476] invalid opcode: 0000 [#3] SMP 
[73757.369623] Modules linked in: nfsd lockd nfs_acl auth_rpcgss sunrpc exportfs cpufreq_powersave cpufreq_userspace cpufreq_ondemand cpufreq_conservative cpufreq_stats freq_table iptable_filter ip_tables x_tables reiserfs aes_i586 dm_crypt dm_mod asb100 hwmon_vid parport_pc lp af_packet parport loop ipv6 psmouse serio_raw button i2c_nforce2 nvidia_agp shpchp pci_hotplug i2c_core agpgart evdev pcspkr ext3 jbd mbcache sr_mod cdrom ata_generic sg sd_mod usbhid hid pata_amd sata_sil sata_promise pata_acpi skge libata scsi_mod ehci_hcd ohci_hcd forcedeth usbcore raid10 raid456 async_xor async_memcpy async_tx xor raid1 raid0 multipath linear md_mod thermal processor fan fbcon tileblit font bitblit softcursor fuse
[73757.373412] 
[73757.373468] Pid: 15174, comm: cat Tainted: G      D (2.6.24-19-generic #1)
[73757.373529] EIP: 0060:[<c01d6ba8>] EFLAGS: 00010212 CPU: 0
[73757.373595] EIP is at sysfs_read_file+0xd8/0xe0
[73757.373652] EAX: 00000001 EBX: dc5fb5c0 ECX: 00000000 EDX: dfa7a5d0
[73757.373712] ESI: 00001000 EDI: dfa7a630 EBP: dc5fb5d4 ESP: f77dff54
[73757.373771]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[73757.373830] Process cat (pid: 15174, ti=f77de000 task=f7d0c5c0 task.ti=f77de000)
[73757.373891] Stack: b7f60ce0 00000000 00001000 08057000 f8892810 f7c9c404 f1c0b820 08057000 
[73757.374367]        c01d6ad0 00001000 c0192327 f77dffa0 00001000 f1c0b820 fffffff7 08057000 
[73757.375812]        f77de000 c0192881 f77dffa0 00000000 00000000 00000000 00000003 00001000 
[73757.376285] Call Trace:
[73757.376395]  [<c01d6ad0>] sysfs_read_file+0x0/0xe0
[73757.376501]  [<c0192327>] vfs_read+0xb7/0x170
[73757.376609]  [<c0192881>] sys_read+0x41/0x70
[73757.376715]  [<c01043c2>] sysenter_past_esp+0x6b/0xa9
[73757.376828]  =======================
[73757.376884] Code: 83 c4 18 5b 5e 5f 5d c3 be ed ff ff ff eb e8 b8 d0 00 00 00 be f4 ff ff ff e8 c5 c8 f9 ff 85 c0 89 43 0c 0f 85 6d ff ff ff eb cc <0f> 0b eb fe 8d 74 26 00 83 ec 14 89 74 24 08 8b 74 24 18 89 7c 
[73757.379906] EIP: [<c01d6ba8>] sysfs_read_file+0xd8/0xe0 SS:ESP 0068:f77dff54
[73757.380075] ---[ end trace 8a9fac7c77d2cf54 ]---

[73760.319674] ------------[ cut here ]------------
[73760.319742] kernel BUG at /build/buildd/linux-2.6.24/fs/sysfs/file.c:126!
[73760.319803] invalid opcode: 0000 [#4] SMP 
[73760.319950] Modules linked in: nfsd lockd nfs_acl auth_rpcgss sunrpc exportfs cpufreq_powersave cpufreq_userspace cpufreq_ondemand cpufreq_conservative cpufreq_stats freq_table iptable_filter ip_tables x_tables reiserfs aes_i586 dm_crypt dm_mod asb100 hwmon_vid parport_pc lp af_packet parport loop ipv6 psmouse serio_raw button i2c_nforce2 nvidia_agp shpchp pci_hotplug i2c_core agpgart evdev pcspkr ext3 jbd mbcache sr_mod cdrom ata_generic sg sd_mod usbhid hid pata_amd sata_sil sata_promise pata_acpi skge libata scsi_mod ehci_hcd ohci_hcd forcedeth usbcore raid10 raid456 async_xor async_memcpy async_tx xor raid1 raid0 multipath linear md_mod thermal processor fan fbcon tileblit font bitblit softcursor fuse
[73760.323741] 
[73760.323796] Pid: 15189, comm: cat Tainted: G      D (2.6.24-19-generic #1)
[73760.323857] EIP: 0060:[<c01d6ba8>] EFLAGS: 00010212 CPU: 0
[73760.323922] EIP is at sysfs_read_file+0xd8/0xe0
[73760.323980] EAX: 00000001 EBX: dc5fb780 ECX: 00000000 EDX: df9e2c90
[73760.324039] ESI: 00001000 EDI: df9e2cf0 EBP: dc5fb794 ESP: dc4fdf54
[73760.324099]  DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
[73760.324158] Process cat (pid: 15189, ti=dc4fc000 task=f762e000 task.ti=dc4fc000)
[73760.324219] Stack: b7f76ce0 00000000 00001000 08057000 f8892810 f7c9c1c4 f18063c0 08057000 
[73760.324693]        c01d6ad0 00001000 c0192327 dc4fdfa0 00001000 f18063c0 fffffff7 08057000 
[73760.325167]        dc4fc000 c0192881 dc4fdfa0 00000000 00000000 00000000 00000003 00001000 
[73760.325641] Call Trace:
[73760.325751]  [<c01d6ad0>] sysfs_read_file+0x0/0xe0
[73760.325856]  [<c0192327>] vfs_read+0xb7/0x170
[73760.325965]  [<c0192881>] sys_read+0x41/0x70
[73760.326071]  [<c01043c2>] sysenter_past_esp+0x6b/0xa9
[73760.326185]  =======================
[73760.326242] Code: 83 c4 18 5b 5e 5f 5d c3 be ed ff ff ff eb e8 b8 d0 00 00 00 be f4 ff ff ff e8 c5 c8 f9 ff 85 c0 89 43 0c 0f 85 6d ff ff ff eb cc <0f> 0b eb fe 8d 74 26 00 83 ec 14 89 74 24 08 8b 74 24 18 89 7c 
[73760.329262] EIP: [<c01d6ba8>] sysfs_read_file+0xd8/0xe0 SS:ESP 0068:dc4fdf54
[73760.329436] ---[ end trace 8a9fac7c77d2cf54 ]---


Don't know if this is the right category. I just felt the need to report this bug, as it showed up in my DMESG.