Description:
Time by time my external USB disk with music "stops working" which results freeze of all applications accessing the disk until I "umount -l /mount/mounted_partitions" and re-connect it to the USB again.
Maybe it's kernel fault, maybe its "hardware issue". But (every) bug should be reported, you know, so here it is... ;-)


Additional info:
May 11 19:27:53 uw000459 kernel: ------------[ cut here ]------------
May 11 19:27:53 uw000459 kernel: WARNING: at fs/buffer.c:1159 mark_buffer_dirty+0x7a/0x90()
May 11 19:27:53 uw000459 kernel: Hardware name: OptiPlex 745
May 11 19:27:53 uw000459 kernel: Modules linked in: nls_cp437 vfat fat fuse snd_usb_audio snd_usb_lib snd_rawmidi uvcvideo videodev v4l1_compat v4l2_compat_ioctl32 tun ipt_MASQUERADE iptable_nat nf_nat nf_conntrack_ipv4 nf_defrag_ipv4 xt_tcpudp xt_conntrack nf_conntrack iptable_filter ip_tables x_tables rfcomm sco bnep l2cap crc16 ipv6 bridge stp llc btusb bluetooth rfkill ext3 jbd ext2 mbcache usb_storage usbhid hid mcs7830 usbnet mii snd_hda_codec_analog snd_seq_dummy snd_seq_oss snd_seq_midi_event snd_seq snd_seq_device snd_hda_intel snd_pcm_oss snd_hda_codec snd_hwdep snd_mixer_oss snd_pcm radeon ttm drm_kms_helper uhci_hcd ehci_hcd psmouse tg3 drm snd_timer snd libphy serio_raw i2c_i801 usbcore evdev iTCO_wdt soundcore i2c_algo_bit snd_page_alloc pcspkr thermal button processor i2c_core dcdbas iTCO_vendor_support ppdev intel_agp sg parport_pc lp kvm_intel kvm parport rtc_cmos rtc_core rtc_lib jfs dm_mod sr_mod sd_mod cdrom ata_piix libata scsi_mod
May 11 19:27:53 uw000459 kernel: Pid: 5855, comm: amarok Not tainted 2.6.33-ARCH #1
May 11 19:27:53 uw000459 kernel: Call Trace:
May 11 19:27:53 uw000459 kernel: [<ffffffff810529f6>] warn_slowpath_common+0x76/0xb0
May 11 19:27:53 uw000459 kernel: [<ffffffff81052a3f>] warn_slowpath_null+0xf/0x20
May 11 19:27:53 uw000459 kernel: [<ffffffff811498aa>] mark_buffer_dirty+0x7a/0x90
May 11 19:27:53 uw000459 kernel: [<ffffffffa04379be>] ext3_put_super+0x29e/0x2e0 [ext3]
May 11 19:27:53 uw000459 kernel: [<ffffffff81122f91>] generic_shutdown_super+0x51/0x100
May 11 19:27:53 uw000459 kernel: [<ffffffff8112306c>] kill_block_super+0x2c/0x50
May 11 19:27:53 uw000459 kernel: [<ffffffff81123f55>] deactivate_super+0x85/0xa0
May 11 19:27:53 uw000459 kernel: [<ffffffff8113c6b3>] mntput_no_expire+0x63/0xb0
May 11 19:27:53 uw000459 kernel: [<ffffffff81122aea>] __fput+0x17a/0x1f0
May 11 19:27:53 uw000459 kernel: [<ffffffff81122b7d>] fput+0x1d/0x30
May 11 19:27:53 uw000459 kernel: [<ffffffff8111f02b>] filp_close+0x5b/0x80
May 11 19:27:53 uw000459 kernel: [<ffffffff81056140>] put_files_struct+0x80/0xf0
May 11 19:27:53 uw000459 kernel: [<ffffffff8105626d>] exit_files+0x4d/0x60
May 11 19:27:53 uw000459 kernel: [<ffffffff81056704>] do_exit+0x164/0x870
May 11 19:27:53 uw000459 kernel: [<ffffffff8105709d>] do_group_exit+0x4d/0xb0
May 11 19:27:53 uw000459 kernel: [<ffffffff81068fe2>] get_signal_to_deliver+0x2d2/0x520
May 11 19:27:53 uw000459 kernel: [<ffffffff810091d0>] do_signal+0x70/0x7b0
May 11 19:27:53 uw000459 kernel: [<ffffffff81041dbb>] ? finish_task_switch+0x4b/0xd0
May 11 19:27:53 uw000459 kernel: [<ffffffff81125a24>] ? vfs_fstatat+0x34/0x70
May 11 19:27:53 uw000459 kernel: [<ffffffff81125a96>] ? vfs_stat+0x16/0x20
May 11 19:27:53 uw000459 kernel: [<ffffffff81009995>] do_notify_resume+0x65/0x80
May 11 19:27:53 uw000459 kernel: [<ffffffff8100a1ce>] int_signal+0x12/0x17
May 11 19:27:53 uw000459 kernel: ---[ end trace 51187fd01a2f3da5 ]---
May 11 19:27:58 uw000459 kernel: usb 3-3: new high speed USB device using ehci_hcd and address 8
May 11 19:27:58 uw000459 kernel: scsi6 : usb-storage 3-3:1.0
May 11 19:28:03 uw000459 kernel: scsi 6:0:0:0: Direct-Access SAMSUNG HM400LI PQ: 0 ANSI: 2
May 11 19:28:03 uw000459 kernel: sd 6:0:0:0: Attached scsi generic sg2 type 0
May 11 19:28:03 uw000459 kernel: sd 6:0:0:0: [sdb] 781422768 512-byte logical blocks: (400 GB/372 GiB)
May 11 19:28:03 uw000459 kernel: sd 6:0:0:0: [sdb] Write Protect is off


Steps to reproduce:
Keep USB disk mounted and use it for a while...