[Bug 2091] New: scp hangs while copying a large file and being executed as a background process ( with nohup )
bugzilla-daemon at mindrot.org
bugzilla-daemon at mindrot.org
Mon Apr 15 22:40:08 EST 2013
https://bugzilla.mindrot.org/show_bug.cgi?id=2091
Bug ID: 2091
Summary: scp hangs while copying a large file and being
executed as a background process ( with nohup )
Classification: Unclassified
Product: Portable OpenSSH
Version: 6.1p1
Hardware: Other
OS: AIX
Status: NEW
Severity: critical
Priority: P5
Component: scp
Assignee: unassigned-bugs at mindrot.org
Reporter: vikas.uit10 at gmail.com
Created attachment 2244
--> https://bugzilla.mindrot.org/attachment.cgi?id=2244&action=edit
Detailed Debug info.
Problem Description -
=====================
scp hangs while copying a large file and being executed as a background
process ( with nohup ).
The following command is used to start an scp copy in the background
and then exit the ksh.
This should allow the user to leave a large file secure copy running
unattended but instead it
results in 2 hung processes as shown at the end of this bug report.
This occurs only with ksh.
nohup scp /tmp/testfile test3 at target_machine:/tmp/testfile &
============================================================================================================
Steps tp Reproduce -
=====================
On the source_machine:
=======================
1. login as user test1
make sure there is a user test1,
2. scp /tmp/testfile test3 at target_machine:/tmp/testfile
make sure ssh server is running on the target machine
make sure the testfile is in folder /tmp/testfile, and is big
enough,
about 780MB.
ls -l /tmp/testfile
-rwxrwxrwx 1 root system 827621072 Aug 31 11:06
/tmp/testfile
3. set up scp, so that scp can be used without prompting for password
cd /home/test1
ssh-keyget -t rsa
This will prompt for a passphrase. Just press the enter key. It'll
then generate an identification
(private key) and a public key.
Your public key has been saved in <your_home_dir>/.ssh/id_rsa.pub,
/home/test1/.ssh/id_rsa.pub
ftp the /home/test1/.ssh/id_rsa.pub file to the target_machine /tmp
folder
On the target_machine:
=======================
1. login as user test3
make sure there is a user test3,
2. set up scp, so scp can be used on the source_machine without
prompting for password
cd /home/test3/.ssh
cat /tmp/id_rsa.pub >> authorized_keys
chmod 700 authorized_keys
3. remove /tmp/testfile if it's existing
rm -i /tmp/testfile
make sure there is no /tmp/testfile existing on the target_machine
before running the scp command
================================================================================================================
Go to the source_machine: ( still login as test1 )
------------------------------------------------------
1. make sure /tmp/testfile is there and big enough
ls -l /tmp/testfile
-rwxrwxrwx 1 root system 827621072 Aug 31 11:06
/tmp/testfile
2. run the scp command
nohup scp /tmp/testfile test3 at target_machine:/tmp/testfile &
Go to the target_machine: ( still login as test3 )
-----------------------------------------------------
make sure the /tmp/testfile is being copied
ls -l /tmp/testfile
-rwxr-xr-x 1 test3 staff 86278144 Sep 01 12:25
/tmp/testfile
ls -l /tmp/testfile
-rwxr-xr-x 1 test3 staff 169050112 Sep 01 12:25
/tmp/testfile
you can see the size is increasing.
Go to the source_machine: ( still login as test1 )
-----------------------------------------------------
completely logout from the source_machine, you should get the
message
of "You have running jobs".
Go to the target_machine: ( still login as test3 )
-----------------------------------------------------
check the size of /tmp/testfile again
ls -l /tmp/testfile
-rwxr-xr-x 1 test3 staff 277184512 Sep 01 12:25
/tmp/testfile
ls -l /tmp/testfile
-rwxr-xr-x 1 test3 staff 277184512 Sep 01 12:25
/tmp/testfile
you can see the size is not increasing any more. The scp has not
finished.
The problem has been reproduced.
====================================================================================================================
Go to the source_machine and login as test1, there were 2 scp related
processes hung after exiting from the ksh -
ps -ef|grep scp
test1 1245328 1 0 16:32:39 - 0:00 scp /tmp/testfile
test3 at target_machine:/tmp/testfile
test1 1638838 1245328 0 16:32:39 - 0:18 /usr//bin/ssh -x
-oForwardAgent no -oPermitLocalCommand no -oClearAllForwardings yes -l
test3 -- target_machine scp -t -- /tmp/testfile
test1 4850090 3998138 0 16:42:59 pts/1 0:00 grep scp
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