sshd throwing signal 6 (sigabrt)

[Ulf Zimmermann]

I have a FreeBSD server (was 5.4-prerelease, now 6-stable as of noon PDT).
On this server I got a problem with sshd throwing signal 6:

Jul 18 15:04:03 log01 sshd[66161]: debug2: User child is on pid 66163
Jul 18 15:04:03 log01 sshd[66163]: debug3: PAM: opening session
Jul 18 15:04:03 log01 sshd[66163]: debug1: PAM: reinitializing credentials
Jul 18 15:04:03 log01 sshd[66163]: debug2: set_newkeys: mode 0
Jul 18 15:04:03 log01 sshd[66163]: debug2: set_newkeys: mode 1
Jul 18 15:04:03 log01 sshd[66163]: debug1: Entering interactive session for SSH2.
Jul 18 15:04:03 log01 sshd[66163]: debug2: fd 5 setting O_NONBLOCK
Jul 18 15:04:03 log01 sshd[66163]: debug2: fd 6 setting O_NONBLOCK
Jul 18 15:04:03 log01 sshd[66163]: debug1: server_init_dispatch_20
Jul 18 15:04:03 log01 sshd[66163]: debug1: server_input_channel_open: ctype session rchan 0 win 131072 max 32768
Jul 18 15:04:03 log01 sshd[66163]: debug1: input_session_request
Jul 18 15:04:03 log01 sshd[66163]: debug1: channel 0: new [server-session]
Jul 18 15:04:03 log01 sshd[66163]: debug1: session_new: init
Jul 18 15:04:03 log01 sshd[66163]: debug1: session_new: session 0
Jul 18 15:04:03 log01 sshd[66163]: debug1: session_open: channel 0
Jul 18 15:04:03 log01 sshd[66163]: debug1: session_open: session 0: link with channel 0
Jul 18 15:04:03 log01 sshd[66163]: debug1: server_input_channel_open: confirm session
Jul 18 15:04:03 log01 sshd[66163]: debug1: server_input_channel_req: channel 0 request exec reply 0
Jul 18 15:04:03 log01 sshd[66163]: debug1: session_by_channel: session 0 channel 0
Jul 18 15:04:03 log01 sshd[66163]: debug1: session_input_channel_req: session 0 req exec
Jul 18 15:04:03 log01 sshd[66163]: debug2: fd 8 setting O_NONBLOCK
Jul 18 15:04:03 log01 sshd[66163]: debug3: fd 8 is O_NONBLOCK
Jul 18 15:04:03 log01 sshd[66163]: debug2: fd 10 setting O_NONBLOCK
Jul 18 15:04:03 log01 sshd[66163]: debug2: channel 0: rcvd eof
Jul 18 15:04:03 log01 sshd[66163]: debug2: channel 0: output open -> drain
Jul 18 15:04:03 log01 sshd[66163]: debug2: channel 0: obuf empty
Jul 18 15:04:03 log01 sshd[66163]: debug2: channel 0: close_write
Jul 18 15:04:03 log01 sshd[66163]: debug2: channel 0: output drain -> closed
Jul 18 15:04:03 log01 pid 66163 (sshd), uid 10042: exited on signal 6

About 80 servers have two cronjobs each starting at the full hour. Each
cronjob has a random sleep of 0 to 900 seconds before it executes ssh/scp/rsync
to copy one or multiple files to that FreeBSD server. One cronjob copies
one file ranging in size 30KB to 300KB. The other cronjob copies 10-30
RRD files, ranging in size from 200KB to 1MB.

Of these about 160 ssh connections in a time range of 15 minutes, I get
1 to 10 errors at the end of the connection. All files get copied as far
I can tell but when the connection closes I see the above signal 6.

On the source side of the ssh connection I get error messages like

"Connection to xxxx closed by remote host"
"ssh_exchange_identification: Connection closed by remote host lost connection"

Anyone have an idea what the problem could be that sshd see sigabrt?

-- 
Regards, Ulf.

---------------------------------------------------------------------
Ulf Zimmermann, 1525 Pacific Ave., Alameda, CA-94501, #: 510-865-0204
You can find my resume at: http://seven.Alameda.net/~ulf/resume.html