loop-AES: timer softirq blocked after USB disconnect?

Hi,

i use loop-AES on a USB flash device. when unplugging the device while 
reading from it, the execution of the timer softirq (and others?) seems 
to be blocked for 250ms. our device has a hardware watchdog that relies 
on a kernel timer to be triggered. i don't observe this behaviour 
without encryption.

the platform is ep9307 (ARM) based, running a linux 2.6.20 and loop-AES 3.2c

below some traces:

[   89.890000] __run_timers()
[   89.900000] __run_timers()
[   89.910000] __run_timers()
[   89.920000] __run_timers()
[   89.930000] __run_timers()
[   89.930000] usb 1-3: USB disconnect, address 2
[   89.940000] __run_timers()
[   89.940000] sd 0:0:0:0: SCSI error: return code = 0x00010000
[   89.940000] end_request: I/O error, dev sda, sector 6981704
[   89.950000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.950000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.960000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   89.970000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   90.230000] __run_timers()
[   90.230000] sd 0:0:0:0: SCSI error: return code = 0x00010000
[   90.240000] end_request: I/O error, dev sda, sector 6981736
[   90.240000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   90.250000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   90.250000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   90.260000] loop1: loop_end_io_transfer err=-5 bi_rw=0x0
[   90.260000] __run_timers()
[   90.280000] __run_timers()
[   90.290000] __run_timers()
[   90.300000] __run_timers()
[   90.310000] __run_timers()
[   90.320000] __run_timers()
[   90.330000] __run_timers()
[   90.340000] __run_timers()

any idea what could be the problem?

begin:vcard
fn:Matthias Kaehlcke
n:Kaehlcke;Matthias
org:Electronic Engineering Solutions;Dept. de Software
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email;internet:[email protected]
title:Ingeniero de Firmware
tel;work:93 407 30 80
tel;fax:93 433 56 71
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url:http://www.e2s.net
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