bugzilla-daemon at bugzilla.mindrot.org
2009-May-15 05:49 UTC
[Bug 1598] New: ssh hangs up on exit
https://bugzilla.mindrot.org/show_bug.cgi?id=1598
Summary: ssh hangs up on exit
Product: Portable OpenSSH
Version: 4.3p2
Platform: All
OS/Version: Linux
Status: NEW
Severity: major
Priority: P2
Component: ssh
AssignedTo: unassigned-bugs at mindrot.org
ReportedBy: beststory at yandex.ru
Description of problem:
Sometimes ssh-session hangs up after remote command already completed.
How reproducible:
Intermittent, no clear understanding on how to reproduce the issue.
Steps to Reproduce:
No clear understanding on how to get this issue.
Actual results:
Ssh-sesson hangs up. Client side can not complete it?s work.
Expected results:
Ssh-session completed successfully and connection Successfully closed.
Additional info:
[root at ibm3-e var]# rpm -aq | grep openssh
openssh-4.3p2-26
openssh-server-4.3p2-26
openssh-askpass-4.3p2-26
openssh-clients-4.3p2-26
uname -a
Linux ibm3-e.asa.merann.ru 2.6.18-53.el5 #1 SMP Wed Oct 10 16:34:02 EDT
2007 i686 i686 i386 GNU/Linux
Some debug information were collected:
1. Strace logs:
root 2953 1 0 Apr02 ? 00:00:00 /usr/sbin/sshd
root 20073 2953 0 Apr07 ? 00:00:00 \_ sshd: nortel [priv]
nortel 20075 20073 0 Apr07 ? 00:00:16 | \_ sshd:
nortel at notty
root 30714 2953 0 10:53 ? 00:00:00 \_ sshd: nortel [priv]
nortel 30728 30714 0 10:53 ? 00:00:00 \_ sshd:
nortel at pts/1
nortel 30729 30728 0 10:53 pts/1 00:00:00 \_ -bash
root 31057 30729 0 10:56 pts/1 00:00:00 \_ su -
?
strace -p 20075
Process 20075 attached - interrupt to quit select(12, [3 6 9 11], [],
NULL, NULL) = 1 (in [3]) rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 read(3,
"%:\5\256\247\245W~\241jP/\270=o\264\213\252\2164\366\377\261\264g\303KfQI\226\353"...,
16384) = 64 write(3,
"\204S\326\265\"\31\3256rr_\361\372zQ\317\325~v|YI\223\265\1\241\32V\224\347\221\250",
32) = 32 select(12, [3 6 9 11], [], NULL, NULL) = 1 (in [3])
rt_sigprocmask(SIG_BLOCK, [CHLD], [], 8) = 0
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0 ?.
Collected debug information from sshd log:
info Apr 15 08:36:48 Apr 15 08:36:48 marcello
pam_unix(system-auth:session): session closed for user root debug Apr
15 08:36:48 Apr 15 08:36:48 marcello debug1: Received SIGCHLD.
debug Apr 15 08:36:48 Apr 15 08:36:48 marcello debug1: session_by_pid:
pid 14897 debug Apr 15 08:36:48 Apr 15 08:36:48 marcello debug1:
session_exit_message: session 0 channel 0 pid 14897 debug Apr 15
08:36:48 Apr 15 08:36:48 marcello debug1: session_exit_message:
release channel 0 <no more messages in the log>
Open descriptors information:
lsof -p 20075 -p 20073
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
sshd 20073 root cwd DIR 3,10 4096 2 /
sshd 20073 root rtd DIR 3,10 4096 2 /
sshd 20073 root txt REG 3,10 391436 372641
/usr/sbin/sshd
sshd 20073 root mem REG 3,10 13420 327725
/lib/libutil-2.5.so
<some libs here>
sshd 20073 root DEL REG 0,8 4389874 /dev/zero
sshd 20073 root DEL REG 0,8 4389866 /dev/zero
sshd 20073 root 0u CHR 1,3 1069 /dev/null
sshd 20073 root 1u CHR 1,3 1069 /dev/null
sshd 20073 root 2u CHR 1,3 1069 /dev/null
sshd 20073 root 3u IPv4 4389854 TCP
vrf2a.bvwpitlab.ca:ssh->em-pit.bvwpitlab.ca:43178 (ESTABLISHED)
sshd 20073 root 4u unix 0xed384740 4389877 socket
sshd 20073 root 6u unix 0xed3843c0 4389882 socket
sshd 20075 nortel cwd DIR 3,10 4096 2 /
sshd 20075 nortel rtd DIR 3,10 4096 2 /
<some libs here>
sshd 20075 nortel DEL REG 0,8 4389874 /dev/zero
sshd 20075 nortel DEL REG 0,8 4389866 /dev/zero
sshd 20075 nortel 0u CHR 1,3 1069 /dev/null
sshd 20075 nortel 1u CHR 1,3 1069 /dev/null
sshd 20075 nortel 2u CHR 1,3 1069 /dev/null
sshd 20075 nortel 3u IPv4 4389854 TCP
vrf2a.bvwpitlab.ca:ssh->em-pit.bvwpitlab.ca:43178 (ESTABLISHED)
sshd 20075 nortel 4u unix 0xed384740 4389877 socket
sshd 20075 nortel 5u unix 0xed384580 4389881 socket
sshd 20075 nortel 6r FIFO 0,6 4389887 pipe
sshd 20075 nortel 7w FIFO 0,6 4389887 pipe
sshd 20075 nortel 9u unix 0xed384900 4389889 socket
sshd 20075 nortel 11u unix 0xed384c80 4389891 socket
select(12, [3 6 9 11], [], NULL, NULL) = 1 (in [3])
sshd 20075 nortel 3u IPv4 4389854 TCP
vrf2a.bvwpitlab.ca:ssh->em-pit.bvwpitlab.ca:43178 (ESTABLISHED)
sshd 20073 root 3u IPv4 4389854 TCP
vrf2a.bvwpitlab.ca:ssh->em-pit.bvwpitlab.ca:43178 (ESTABLISHED)
During another round of testing new kernel with some fix of another ssh
issue were used and this issue still can be observed even with a newer
kernel:
?kernel-2.6.18-128.el5.it265105.i686.rpm?
https://bugzilla.redhat.com/show_bug.cgi?id=448328
Red Hat Bugzilla ? Bug 448328
I believe that is could be know openssh issue:
http://brneurosci.org/linuxsetup54.html
My initial investigation shows that it is looks like the issue that
could be fixed with suggested patch.
I the web-page above claims that this issue already fixed I tried to
check session.c in CSV but did not find this fix in. Were it actually
fixed?
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bugzilla-daemon at bugzilla.mindrot.org
2009-May-15 05:52 UTC
[Bug 1598] ssh hangs up on exit
https://bugzilla.mindrot.org/show_bug.cgi?id=1598
Damien Miller <djm at mindrot.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |djm at mindrot.org
--- Comment #1 from Damien Miller <djm at mindrot.org> 2009-05-15
15:52:22 ---
Can you recreate this with a recent OpenSSH version (e.g. 5.2p1)? Your
version is three years old and we have fixed quite a few bugs, some
related to hangs at exit time.
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bugzilla-daemon at bugzilla.mindrot.org
2009-May-15 06:45 UTC
[Bug 1598] ssh hangs up on exit
https://bugzilla.mindrot.org/show_bug.cgi?id=1598 --- Comment #2 from KateB <beststory at yandex.ru> 2009-05-15 16:45:20 --- The issue is intermittent. I will try to check it with new version. -- Configure bugmail: https://bugzilla.mindrot.org/userprefs.cgi?tab=email ------- You are receiving this mail because: ------- You are watching the assignee of the bug. You are watching someone on the CC list of the bug.
bugzilla-daemon at bugzilla.mindrot.org
2011-Oct-04 14:02 UTC
[Bug 1598] ssh hangs up on exit
https://bugzilla.mindrot.org/show_bug.cgi?id=1598
Damien Miller <djm at mindrot.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |WORKSFORME
--- Comment #3 from Damien Miller <djm at mindrot.org> 2011-10-05 01:02:30
EST ---
Couldn't reproduce with a recent version within two years = no bug
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