BUG: soft lockup - CPU#0 stuck for 74s! [ksoftirqd/0:4]
Modules linked in: cryptd aes_x86_64 aes_generic snd_usb_audio snd_usb_lib arc4 snd_hda_codec_realtek joydev binfmt_misc ppdev snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer snd_seq_device parport_pc hid_microsoft gspca_zc3xx gspca_main videodev v4l1_compat v4l2_compat_ioctl32 fbcon tileblit font bitblit softcursor usb_storage snd soundcore snd_page_alloc amd64_edac_mod ath5k mac80211 ath lp cfg80211 led_class nvidia(P) asus_atk0110 vga16fb edac_core vgastate edac_mce_amd psmouse serio_raw k8temp i2c_viapro shpchp parport usbhid hid floppy pata_jmicron ahci
CPU 0:
Modules linked in: cryptd aes_x86_64 aes_generic snd_usb_audio snd_usb_lib arc4 snd_hda_codec_realtek joydev binfmt_misc ppdev snd_hda_intel snd_hda_codec snd_hwdep snd_pcm_oss snd_mixer_oss snd_pcm snd_seq_dummy snd_seq_oss snd_seq_midi snd_rawmidi snd_seq_midi_event snd_seq snd_timer snd_seq_device parport_pc hid_microsoft gspca_zc3xx gspca_main videodev v4l1_compat v4l2_compat_ioctl32 fbcon tileblit font bitblit softcursor usb_storage snd soundcore snd_page_alloc amd64_edac_mod ath5k mac80211 ath lp cfg80211 led_class nvidia(P) asus_atk0110 vga16fb edac_core vgastate edac_mce_amd psmouse serio_raw k8temp i2c_viapro shpchp parport usbhid hid floppy pata_jmicron ahci
Pid: 4, comm: ksoftirqd/0 Tainted: P           2.6.32-21-generic #32-Ubuntu System Product Name
RIP: 0010:[<ffffffff8137fda1>]  [<ffffffff8137fda1>] scsi_pool_free_command+0x1/0x60
RSP: 0018:ffff880001c03d68  EFLAGS: 00000286
RAX: 0000000000000282 RBX: ffff880001c03d98 RCX: ffff88007be7d838
RDX: ffff8800766b8830 RSI: ffff88007ad73e00 RDI: ffffffff817f34e0
RBP: ffffffff81013cb3 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000000 R12: ffff880001c03ce0
R13: ffff88007ad73e00 R14: ffff8800766b8800 R15: ffffffff81545f5c
FS:  00007ff3c54e47a0(0000) GS:ffff880001c00000(0000) knlGS:00000000f76246c0
CS:  0010 DS: 0018 ES: 0018 CR0: 000000008005003b
CR2: 00007f5f24db7000 CR3: 000000006f196000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <IRQ>  [<ffffffff8137fe5b>] ? __scsi_put_command+0x5b/0xa0
 [<ffffffff8137ff01>] ? scsi_put_command+0x61/0x70
 [<ffffffff8138706a>] ? scsi_next_command+0x3a/0x60
 [<ffffffff813878fb>] ? scsi_end_request+0xab/0xb0
 [<ffffffff81387c03>] ? scsi_io_completion+0xa3/0x500
 [<ffffffff8137f6a2>] ? scsi_finish_command+0xc2/0x130
 [<ffffffff813881cd>] ? scsi_softirq_done+0x14d/0x170
 [<ffffffff812a3635>] ? blk_done_softirq+0x85/0xa0
 [<ffffffff8106e3a7>] ? __do_softirq+0xb7/0x1e0
 [<ffffffff810142ec>] ? call_softirq+0x1c/0x30
 <EOI>  [<ffffffff81015cb5>] ? do_softirq+0x65/0xa0
 [<ffffffff8106def0>] ? ksoftirqd+0x80/0x110
 [<ffffffff8106de70>] ? ksoftirqd+0x0/0x110
 [<ffffffff81084fa6>] ? kthread+0x96/0xa0
 [<ffffffff810141ea>] ? child_rip+0xa/0x20
 [<ffffffff81084f10>] ? kthread+0x0/0xa0
 [<ffffffff810141e0>] ? child_rip+0x0/0x20