[ 1918.565197] INFO: task fastboot:4101 blocked for more than 120 seconds.
[ 1918.565205]       Tainted: P           OE  3.19.0-21-generic #21-Ubuntu
[ 1918.565208] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
[ 1918.565211] fastboot        D ffff8801dc9a3b88     0  4101   4098 0x00000000
[ 1918.565218]  ffff8801dc9a3b88 ffff880072c3b110 0000000000014200 ffff8801dc9a3fd8
[ 1918.565223]  0000000000014200 ffff880235e00000 ffff880072c3b110 ffffffff003d4210
[ 1918.565228]  ffff8801dc9a3cd8 7fffffffffffffff ffff8801dc9a3cd0 ffff880072c3b110
[ 1918.565233] Call Trace:
[ 1918.565246]  [<ffffffff817c6569>] schedule+0x29/0x70
[ 1918.565252]  [<ffffffff817c9b4c>] schedule_timeout+0x20c/0x280
[ 1918.565259]  [<ffffffff817c7424>] wait_for_completion_timeout+0xa4/0x180
[ 1918.565264]  [<ffffffff810a2f70>] ? wake_up_state+0x20/0x20
[ 1918.565271]  [<ffffffff815bfbbd>] usb_start_wait_urb+0x7d/0x150
[ 1918.565276]  [<ffffffff811d7ad9>] ? __kmalloc+0x1c9/0x280
[ 1918.565282]  [<ffffffff815c00dd>] usb_bulk_msg+0xbd/0x170
[ 1918.565287]  [<ffffffff815cad6a>] proc_bulk+0x22a/0x3a0
[ 1918.565292]  [<ffffffff810b6e65>] ? __wake_up_common+0x55/0x90
[ 1918.565297]  [<ffffffff815cc480>] usbdev_do_ioctl+0x840/0x1040
[ 1918.565313]  [<ffffffff81356172>] ? common_file_perm+0x42/0xf0
[ 1918.565318]  [<ffffffff815cccae>] usbdev_ioctl+0xe/0x20
[ 1918.565323]  [<ffffffff81209230>] do_vfs_ioctl+0x2e0/0x4e0
[ 1918.565328]  [<ffffffff811f4b7c>] ? vfs_write+0x15c/0x1f0
[ 1918.565333]  [<ffffffff812094b1>] SyS_ioctl+0x81/0xa0
[ 1918.565338]  [<ffffffff817caecd>] system_call_fastpath+0x16/0x1b