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Re: timeout problem in ssh sessions
- X-seq: zsh-users 12555
- From: Andy Spiegl <zsh.Andy@xxxxxxxxx>
- To: ZSH User List <zsh-users@xxxxxxxxxx>
- Subject: Re: timeout problem in ssh sessions
- Date: Wed, 13 Feb 2008 00:29:47 +0100
- In-reply-to: <080212083755.ZM20121@xxxxxxxxxxxxxxxxxxxxxx>
- Kreccount: 1
- Mail-followup-to: ZSH User List <zsh-users@xxxxxxxxxx>
- Mailing-list: contact zsh-users-help@xxxxxxxxxx; run by ezmlm
- References: <20080211233404.GA13398@xxxxxxxxx> <080212083755.ZM20121@xxxxxxxxxxxxxxxxxxxxxx>
On 2008-02-12, 08:37, Bart Schaefer wrote:
> If you have or can install "lsof" it would be very interesting to find
> out to what file descriptor 3 is connected -- or more generally, what
> are all the open descriptors in ssh, after the zsh process has exited.
I tried harder this time. According to the proc fs it's a socket:
condor:/proc/13138/fd#ll
insgesamt 0
lr-x------ 1 root root 64 12. Feb 23:55 0 -> /dev/null
l-wx------ 1 root root 64 12. Feb 23:55 1 -> pipe:[16122]
l-wx------ 1 root root 64 12. Feb 23:55 2 -> pipe:[16122]
lrwx------ 1 root root 64 12. Feb 23:55 3 -> socket:[37169512]
lr-x------ 1 root root 64 12. Feb 23:55 4 -> /dev/null
lrwx------ 1 root root 64 12. Feb 23:55 5 -> /dev/ptmx
The particular process was:
USER PID PPID S CPU %MEM RSS VSZ START ELAPSED TIME CMD
spiegl 13138 1 S - 0.1 5332 10024 23:54 03:00 0:00 xterm -title root@condor -geometry 105x45 -e ssh -l root localhost
spiegl 13139 13138 S - 0.0 2232 4992 23:54 03:00 0:00 ssh -l root localhost
(as you can see, zsh had already terminated)
The strace output of this particular process looked like this:
...
write(3, "\0204\20\16\206\360o\3530=\307,W\221\305\212F\255\250\236"..., 32) = 32
select(9, [3 8], [], NULL, NULL) = 1 (in [3])
read(3, "\304k\346\203T)\220N\222RG\255\177j\331\37\23{\360\323"..., 8192) = 64
select(9, [3 8], [3], NULL, NULL) = 1 (out [3])
write(3, "9Q\320\323:\341;\227s\361\331\315\345\333\336\210ON\375"..., 32) = 32
select(9, [3 8], [], NULL, NULL) = 1 (in [8])
read(8, "\35\17\26\0\320\240\340\17\1\0`\6\276\1\0\0\0\20\0\0\0"..., 16384) = 32
select(9, [3 8], [3], NULL, NULL) = 1 (out [3])
write(3, "3O\0003\362\17\235\267\354\331\35be\337\245\270F\271\203"..., 80) = 80
select(9, [3 8], [], NULL, NULL) = 1 (in [3])
read(3, "9\322\247\16\10\201\265Dus\305J\345\2654\364\342\367\374"..., 8192) = 32
shutdown(8, 1 /* send */) = 0
select(9, [3], [3], NULL, NULL) = 1 (out [3])
write(3, ",5\230\22\300\252\341\220\23a\35\315\253Ny\346$\335\3|"..., 64) = 64
select(9, [3], [], NULL, NULL) = 1 (in [3])
read(3, "\267\200_>4\331c\234\215}\31\277\325\264\342R\320p\274"..., 8192) = 32
shutdown(8, 2 /* send and receive */) = 0
close(8) = 0
close(8) = -1 EBADF (Bad file descriptor)
close(8) = -1 EBADF (Bad file descriptor)
rt_sigaction(SIGWINCH, NULL, {0x8000b9c0, [], 0}, 8) = 0
rt_sigaction(SIGWINCH, {SIG_DFL}, NULL, 8) = 0
ioctl(0, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(1, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
ioctl(2, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon echo ...}) = 0
write(2, "Connection to localhost closed.\r"..., 33) = 33
gettimeofday({1202857222, 359943}, NULL) = 0
shutdown(3, 2 /* send and receive */) = 0
close(3) = 0
brk(0x8007f000) = 0x8007f000
exit_group(0) = ?
Process 13139 detached
After "select(9, [3]..." it was always pausing for several seconds.
Then finally the ssh and xterm window closed.
> It looks from the strace output as if it might be something related to
> the ssh-agent
The ssh-agent had PID 7656 and these file descriptors:
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
ssh-agent 7656 spiegl cwd DIR 8,6 4096 2 /
ssh-agent 7656 spiegl rtd DIR 8,6 4096 2 /
ssh-agent 7656 spiegl txt REG 8,6 77220 15189338 /usr/bin/ssh-agent
ssh-agent 7656 spiegl mem REG 8,6 41812070 /lib/libkeyutils-1.2.so (path inode=41812034)
ssh-agent 7656 spiegl mem REG 8,6 27588 55216405 /usr/lib/libkrb5support.so.0.1
ssh-agent 7656 spiegl mem REG 8,6 15220746 /lib/i686/cmov/libdl-2.7.so (path inode=37373103)
ssh-agent 7656 spiegl mem REG 8,6 15220743 /lib/i686/cmov/libc-2.7.so (path inode=37373099)
ssh-agent 7656 spiegl mem REG 8,6 41811981 /lib/libcom_err.so.2.1 (path inode=41812032)
ssh-agent 7656 spiegl mem REG 8,6 143296 55216401 /usr/lib/libk5crypto.so.3.1
ssh-agent 7656 spiegl mem REG 8,6 582740 55216403 /usr/lib/libkrb5.so.3.3
ssh-agent 7656 spiegl mem REG 8,6 167960 55216316 /usr/lib/libgssapi_krb5.so.2.2
ssh-agent 7656 spiegl mem REG 8,6 15220745 /lib/i686/cmov/libcrypt-2.7.so (path inode=37373102)
ssh-agent 7656 spiegl mem REG 8,6 15220749 /lib/i686/cmov/libnsl-2.7.so (path inode=37373108)
ssh-agent 7656 spiegl mem REG 8,6 55215392 /usr/lib/libz.so.1.2.3.3 (path inode=55215466)
ssh-agent 7656 spiegl mem REG 8,6 15220762 /lib/i686/cmov/libutil-2.7.so (path inode=37373124)
ssh-agent 7656 spiegl mem REG 8,6 56181144 /usr/lib/i686/cmov/libcrypto.so.0.9.8 (path inode=56180982)
ssh-agent 7656 spiegl mem REG 8,6 15220758 /lib/i686/cmov/libresolv-2.7.so (path inode=37373120)
ssh-agent 7656 spiegl mem REG 8,6 41812019 /lib/ld-2.7.so (path inode=41811982)
ssh-agent 7656 spiegl 0u CHR 1,3 97 /dev/null
ssh-agent 7656 spiegl 1u CHR 1,3 97 /dev/null
ssh-agent 7656 spiegl 2u CHR 1,3 97 /dev/null
ssh-agent 7656 spiegl 3u unix 0xf37196c0 15673 /tmp/ssh-KVjaJd7584/agent.7584
ssh-agent 7656 spiegl 5w FIFO 0,5 14681 pipe
ssh-agent 7656 spiegl 7r FIFO 0,5 14685 pipe
The parent xterm:
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
xterm 13138 spiegl cwd DIR 8,6 24576 20348937 /home/spiegl
xterm 13138 spiegl rtd DIR 8,6 4096 2 /
xterm 13138 spiegl txt REG 8,6 317648 15189861 /usr/bin/xterm
xterm 13138 spiegl mem REG 8,6 14396 55219117 /usr/lib/libXfixes.so.3.1.0
xterm 13138 spiegl mem REG 8,6 32764 55216382 /usr/lib/libXcursor.so.1.0.2
xterm 13138 spiegl mem REG 8,6 2283360 56968903 /usr/lib/locale/locale-archive
xterm 13138 spiegl mem REG 8,6 112354 37373119 /lib/i686/cmov/libpthread-2.7.so
xterm 13138 spiegl mem REG 8,6 9684 37373103 /lib/i686/cmov/libdl-2.7.so
xterm 13138 spiegl mem REG 8,6 16704 55220633 /usr/lib/libXdmcp.so.6.0.0
xterm 13138 spiegl mem REG 8,6 7220 55220621 /usr/lib/libXau.so.6.0.0
xterm 13138 spiegl mem REG 8,6 60776 37290193 /usr/lib/libXpm.so.4.11.0
xterm 13138 spiegl mem REG 8,6 126508 55216060 /usr/lib/libexpat.so.1.0.0
xterm 13138 spiegl mem REG 8,6 30544 55216369 /usr/lib/libXrender.so.1.3.0
xterm 13138 spiegl mem REG 8,6 81012 55215466 /usr/lib/libz.so.1.2.3.3
xterm 13138 spiegl mem REG 8,6 449240 55215678 /usr/lib/libfreetype.so.6.3.16
xterm 13138 spiegl mem REG 8,6 1356196 37373099 /lib/i686/cmov/libc-2.7.so
xterm 13138 spiegl mem REG 8,6 195564 41812031 /lib/libncurses.so.5.6
xterm 13138 spiegl mem REG 8,6 965952 55221003 /usr/lib/libX11.so.6.2.0
xterm 13138 spiegl mem REG 8,6 84880 28971387 /usr/lib/libICE.so.6.3.0
xterm 13138 spiegl mem REG 8,6 27944 55215460 /usr/lib/libSM.so.6.0.0
xterm 13138 spiegl mem REG 8,6 324484 55221345 /usr/lib/libXt.so.6.0.0
xterm 13138 spiegl mem REG 8,6 52848 55221313 /usr/lib/libXext.so.6.4.0
xterm 13138 spiegl mem REG 8,6 85528 55216599 /usr/lib/libXmu.so.6.2.0
xterm 13138 spiegl mem REG 8,6 363848 28971543 /usr/lib/libXaw7.so.7.0.0
xterm 13138 spiegl mem REG 8,6 168432 28968817 /usr/lib/libfontconfig.so.1.3.0
xterm 13138 spiegl mem REG 8,6 70088 55219304 /usr/lib/libXft.so.2.1.2
xterm 13138 spiegl mem REG 8,6 9480 55774283 /usr/lib/gconv/ISO8859-15.so
xterm 13138 spiegl mem REG 8,6 25700 55771214 /usr/lib/gconv/gconv-modules.cache
xterm 13138 spiegl mem REG 8,6 117344 41811982 /lib/ld-2.7.so
xterm 13138 spiegl 0r CHR 1,3 97 /dev/null
xterm 13138 spiegl 1w FIFO 0,5 16122 pipe
xterm 13138 spiegl 2w FIFO 0,5 16122 pipe
xterm 13138 spiegl 3u unix 0xddbfdb80 37169512 socket
xterm 13138 spiegl 4r CHR 1,3 97 /dev/null
xterm 13138 spiegl 5u CHR 5,2 490 /dev/ptmx
The parent ssh:
COMMAND PID USER FD TYPE DEVICE SIZE NODE NAME
ssh 13139 spiegl cwd DIR 8,6 24576 20348937 /home/spiegl
ssh 13139 spiegl rtd DIR 8,6 4096 2 /
ssh 13139 spiegl txt REG 8,6 288032 15188742 /usr/bin/ssh
ssh 13139 spiegl mem REG 8,6 38412 37373111 /lib/i686/cmov/libnss_files-2.7.so
ssh 13139 spiegl mem REG 8,6 34352 37373114 /lib/i686/cmov/libnss_nis-2.7.so
ssh 13139 spiegl mem REG 8,6 30436 37373109 /lib/i686/cmov/libnss_compat-2.7.so
ssh 13139 spiegl mem REG 8,6 5564 41812034 /lib/libkeyutils-1.2.so
ssh 13139 spiegl mem REG 8,6 27588 55216405 /usr/lib/libkrb5support.so.0.1
ssh 13139 spiegl mem REG 8,6 9684 37373103 /lib/i686/cmov/libdl-2.7.so
ssh 13139 spiegl mem REG 8,6 1356196 37373099 /lib/i686/cmov/libc-2.7.so
ssh 13139 spiegl mem REG 8,6 7364 41812032 /lib/libcom_err.so.2.1
ssh 13139 spiegl mem REG 8,6 143296 55216401 /usr/lib/libk5crypto.so.3.1
ssh 13139 spiegl mem REG 8,6 582740 55216403 /usr/lib/libkrb5.so.3.3
ssh 13139 spiegl mem REG 8,6 167960 55216316 /usr/lib/libgssapi_krb5.so.2.2
ssh 13139 spiegl mem REG 8,6 38300 37373102 /lib/i686/cmov/libcrypt-2.7.so
ssh 13139 spiegl mem REG 8,6 83708 37373108 /lib/i686/cmov/libnsl-2.7.so
ssh 13139 spiegl mem REG 8,6 81012 55215466 /usr/lib/libz.so.1.2.3.3
ssh 13139 spiegl mem REG 8,6 9696 37373124 /lib/i686/cmov/libutil-2.7.so
ssh 13139 spiegl mem REG 8,6 1338692 56180982 /usr/lib/i686/cmov/libcrypto.so.0.9.8
ssh 13139 spiegl mem REG 8,6 67408 37373120 /lib/i686/cmov/libresolv-2.7.so
ssh 13139 spiegl mem REG 8,6 117344 41811982 /lib/ld-2.7.so
ssh 13139 spiegl 0u CHR 136,21 23 /dev/pts/21
ssh 13139 spiegl 1u CHR 136,21 23 /dev/pts/21
ssh 13139 spiegl 2u CHR 136,21 23 /dev/pts/21
ssh 13139 spiegl 3u IPv4 37169532 TCP localhost:35553->localhost:ssh (ESTABLISHED)
ssh 13139 spiegl 4r CHR 1,3 97 /dev/null
ssh 13139 spiegl 8u unix 0xe3d23180 37173322 socket
sshd 13140 root cwd DIR 8,6 4096 2 /
sshd 13140 root rtd DIR 8,6 4096 2 /
sshd 13140 root txt REG 8,6 359780 55148866 /usr/sbin/sshd
sshd 13140 root DEL REG 0,8 37169565 /dev/zero
sshd 13140 root mem REG 8,6 47300 12927146 /lib/security/pam_unix.so
sshd 13140 root DEL REG 0,8 37169556 /dev/zero
sshd 13140 root mem REG 8,6 38412 37373111 /lib/i686/cmov/libnss_files-2.7.so
sshd 13140 root mem REG 8,6 34352 37373114 /lib/i686/cmov/libnss_nis-2.7.so
sshd 13140 root mem REG 8,6 30436 37373109 /lib/i686/cmov/libnss_compat-2.7.so
sshd 13140 root mem REG 8,6 5564 41812034 /lib/libkeyutils-1.2.so
sshd 13140 root mem REG 8,6 27588 55216405 /usr/lib/libkrb5support.so.0.1
sshd 13140 root mem REG 8,6 1356196 37373099 /lib/i686/cmov/libc-2.7.so
sshd 13140 root mem REG 8,6 7364 41812032 /lib/libcom_err.so.2.1
sshd 13140 root mem REG 8,6 143296 55216401 /usr/lib/libk5crypto.so.3.1
sshd 13140 root mem REG 8,6 582740 55216403 /usr/lib/libkrb5.so.3.3
sshd 13140 root mem REG 8,6 167960 55216316 /usr/lib/libgssapi_krb5.so.2.2
sshd 13140 root mem REG 8,6 38300 37373102 /lib/i686/cmov/libcrypt-2.7.so
sshd 13140 root mem REG 8,6 83708 37373108 /lib/i686/cmov/libnsl-2.7.so
sshd 13140 root mem REG 8,6 81012 55215466 /usr/lib/libz.so.1.2.3.3
sshd 13140 root mem REG 8,6 9696 37373124 /lib/i686/cmov/libutil-2.7.so
sshd 13140 root mem REG 8,6 1338692 56180982 /usr/lib/i686/cmov/libcrypto.so.0.9.8
sshd 13140 root mem REG 8,6 67408 37373120 /lib/i686/cmov/libresolv-2.7.so
sshd 13140 root mem REG 8,6 91860 41811976 /lib/libselinux.so.1
sshd 13140 root mem REG 8,6 9684 37373103 /lib/i686/cmov/libdl-2.7.so
sshd 13140 root mem REG 8,6 37600 41811991 /lib/libpam.so.0.81.6
sshd 13140 root mem REG 8,6 31224 41812003 /lib/libwrap.so.0.7.6
sshd 13140 root mem REG 8,6 12208 12927039 /lib/security/pam_limits.so
sshd 13140 root mem REG 8,6 7808 12927043 /lib/security/pam_mail.so
sshd 13140 root mem REG 8,6 3708 12927045 /lib/security/pam_motd.so
sshd 13140 root mem REG 8,6 4260 12927133 /lib/security/pam_nologin.so
sshd 13140 root mem REG 8,6 10188 12927030 /lib/security/pam_env.so
sshd 13140 root mem REG 8,6 117344 41811982 /lib/ld-2.7.so
sshd 13140 root 0u CHR 1,3 97 /dev/null
sshd 13140 root 1u CHR 1,3 97 /dev/null
sshd 13140 root 2u CHR 1,3 97 /dev/null
sshd 13140 root 3r IPv4 37169533 TCP localhost:ssh->localhost:35553 (ESTABLISHED)
sshd 13140 root 4w FIFO 0,5 37169566 pipe
sshd 13140 root 5u FIFO 0,5 37169566 pipe
sshd 13140 root 7u unix 0xf229b700 37169615 /tmp/ssh-RKePv13140/agent.13140
sshd 13140 root 11u IPv4 37173321 TCP localhost:6014->localhost:44057 (ESTABLISHED)
I also tried to find the strace lines where this socket is opened.
Should be this:
munmap(0xb7f0e000, 4096) = 0
socket(PF_INET, SOCK_STREAM, IPPROTO_TCP) = 3
connect(3, {sa_family=AF_INET, sin_port=htons(22), sin_addr=inet_addr("127.0.0.1")}, 16) = 0
setsockopt(3, SOL_SOCKET, SO_KEEPALIVE, [1], 4) = 0
Lateron I found:
read(3, "S", 1) = 1
read(3, "S", 1) = 1
read(3, "H", 1) = 1
read(3, "-", 1) = 1
read(3, "2", 1) = 1
read(3, ".", 1) = 1
read(3, "0", 1) = 1
read(3, "-", 1) = 1
read(3, "O", 1) = 1
read(3, "p", 1) = 1
read(3, "e", 1) = 1
read(3, "n", 1) = 1
read(3, "S", 1) = 1
read(3, "S", 1) = 1
read(3, "H", 1) = 1
read(3, "_", 1) = 1
read(3, "4", 1) = 1
read(3, ".", 1) = 1
read(3, "7", 1) = 1
read(3, "p", 1) = 1
read(3, "1", 1) = 1
read(3, " ", 1) = 1
read(3, "D", 1) = 1
read(3, "e", 1) = 1
read(3, "b", 1) = 1
read(3, "i", 1) = 1
read(3, "a", 1) = 1
read(3, "n", 1) = 1
read(3, "-", 1) = 1
read(3, "3", 1) = 1
read(3, "\n", 1) = 1
write(3, "SSH-2.0-OpenSSH_4.7p1 Debian-3\n", 31) = 31
fcntl64(3, F_GETFL) = 0x2 (flags O_RDWR)
fcntl64(3, F_SETFL, O_RDWR|O_NONBLOCK) = 0
write(3, "\0\0\3\24\10\24\327l\7\245h\'~\0047\6\364\377\376\215\252"..., 792) = 792
select(4, [3], NULL, NULL, NULL) = 1 (in [3])
read(3, "\0\0\3\f\n\24\322*9\1\225\30763\314\263\275\217y;\23\220"..., 8192) = 784
write(3, "\0\0\0\24\6\"\0\0\4\0\0\0\4\0\0\0 \0\0\0\0\0\0\0", 24) = 24
That seems to be the ssh data connection itself, right?
Does this make sense to you?
Andy.
--
BREAKFAST.SYS halted... Cereal port not responding.
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