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On Tuesday 22 February 2005 03:41 pm, Alan Stern wrote:

Alan,
See below for stack traces and also note that the stack traces are after I
modified usb_device_read to do down_interruptible instead of down. (kudzu
gets stuck regardless though.) Let me know if you want me to revert the
down_interruptible change and repost the stack trace.

I wrongly related this to the 2 minute hang - this one is forever if I let
kudzu start during boot. If I run kudzu after boot is complete, it gets stuck
and everything else on that drive (mount, unmount ..) also gets stuck. Sorry
about the confusion.

Attached is the disassembly of usb_device_read from my machine.

Parag

SysRQ + T for relevant processes
======================
hald D 00000020e12be31a 0 2558 1 3272 2545
(NOTLB)
ffff81002c76fb48 0000000000000082 ffff81002c76fb28 ffffffff88515044
000000862c76fb08 ffff81002eb10800 0000000000000249 ffff810001c56030
ffff81002c76fc08 0000000000000002
Call Trace: <{:scsi_mod:scsi_request_fn+2356}
<{io_schedule+15}<{sync_page+70}
<{__wait_on_bit_lock+69} <{sync_page+0}
<{__lock_page+167} <{wake_bit_function+0}
<{wake_bit_function+0} <{do_generic_mapping_read+660}
<{file_read_actor+0} <{__generic_file_aio_read+420}
<{generic_file_read+187} <{autoremove_wake_function+0}
<{do_brk+720}<{vfs_read+225}
<{sys_read+80}<{system_call+126}

scsi_eh_2 D 00000000ffffffff 0 3581 1 3582 3277
(L-TLB)
ffff81002bdc1d88 0000000000000046 00000000000001e3 ffff81002bed8800
ffff81002bdc1d48 ffff81002c25a800 0000000000000812 ffffffff803df080
ffff81002bdc1ed0 ffff81002c25a800
Call Trace:
<{wait_for_completion+437} <{default_wake_function+0}
<{default_wake_function+0} <{:usb_storage:usb_stor_stop_transport+35}
<{:usb_storage:command_abort+256}
<{:scsi_mod:scsi_error_handler+2172}
<{child_rip+8} <{:scsi_mod:scsi_error_handler+0}
<{child_rip+0}
usb-storage D 00000000ffffffff 0 3582 1 3627 3581
(L-TLB)
ffff81002b8e1c08 0000000000000046 ffff81002b9e1000 0000000000000010
000000762b8e1c98 ffff81002bed8800 00000000000003dd ffff81002eb10800
00000000c0040280 000000000000001f
Call Trace:
<{wait_for_completion+437} <{thread_return+253}
<{default_wake_function+0} <{default_wake_function+0}
<{:usb_storage:usb_stor_msg_common+550}
<