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I'm running an rsync between two external USB 2TB drives to make a copy on a CentOS 5.9 server. It appears to have stalled, and it hangs when I cd to the source drive in the copy, while the destination drive is accessible. When I do a 'df' command, it shows no advancement in the copying.

When I do a 'dmesg' I see this output I never saw before:

INFO: task rsync:3108 blocked for more than 120 seconds.
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
rsync         D 000011E8  2160  3108   3105  3109               (NOTLB)
       d1c3ddcc 00000082 46745343 000011e8 c04601e6 00000044 00000000 0000000a 
       d73a9550 467cd3ea 000011e8 000880a7 00000000 d73a965c c1506700 e6a4ec80 
       c0461802 e889b75f 00000000 00e5ba3a 02570c3a c042e4a3 c1506bbc 02570c3a 
Call Trace:
 [<c04601e6>] __alloc_pages+0x69/0x2cf
 [<c0461802>] __do_page_cache_readahead+0x117/0x178
 [<e889b75f>] ext3_get_block+0x0/0xd6 [ext3]
 [<c042e4a3>] getnstimeofday+0x30/0xb6
 [<c06278a0>] io_schedule+0x36/0x59
 [<c045babe>] sync_page+0x0/0x3b
 [<c045baf6>] sync_page+0x38/0x3b
 [<c06279b2>] __wait_on_bit_lock+0x2a/0x52
 [<c045ba39>] __lock_page+0x52/0x59
 [<c0438220>] wake_bit_function+0x0/0x3c
 [<c045c265>] do_generic_mapping_read+0x1f7/0x382
 [<c045cc69>] __generic_file_aio_read+0x16a/0x1a3
 [<c045b72b>] file_read_actor+0x0/0xd5
 [<c045ccdf>] generic_file_aio_read+0x3d/0x44
 [<c0478f3b>] do_sync_read+0xb6/0xf1
 [<c04381f3>] autoremove_wake_function+0x0/0x2d
 [<c044e6c7>] audit_syscall_entry+0x193/0x1bd
 [<c0478e85>] do_sync_read+0x0/0xf1
 [<c0479814>] vfs_read+0x9f/0x141
 [<c0479cc6>] sys_read+0x3c/0x63
 [<c0404f4b>] syscall_call+0x7/0xb

Can I kill the processes? If so, in which order? Which processes? Some are in state S and D. Can anyone explain what is going on? Thanks!

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This may be a bug with CentOS 5.9 using i386 kernel, because I moved the two external hard disks to a CentOS 6.3 x86_64 machine and it completed this rsync without a problem.

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