Date: Fri, 14 Jul 2023 09:35:45 -0400 From: mike tancsa <mike@sentex.net> To: Doug Hardie <bc979@lafn.org>, questions@freebsd.org Subject: Re: Random sshd hangs Message-ID: <af0c07dc-a8c3-2657-881e-0341b47b2d72@sentex.net> In-Reply-To: <30FBD752-56E4-4A18-8EB9-54E9F4D0EF98@sermon-archive.info> References: <30FBD752-56E4-4A18-8EB9-54E9F4D0EF98@sermon-archive.info>
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On 7/13/2023 11:14 PM, Doug Hardie wrote: > After somewhere around 5-10 minutes, everything returns to normal. > This is not consistent. I can run the program 10 time fine before the > next hang. There is nothing I have found that is common to the hangs. > Now that I have the program running correctly, the system never seems > to hang again. All my ideas on what is causing this are not supported > by the facts. It's not a core dump issue. It does not appear to be > an IP issue as IP continues to work, as do new ssh connections. The > web server is sitting there completely idle. It never receives any > requests. I suppose it could be something in libgd, but it would seem > that would be continuing even now. I am a lot confused over this. I > don't want to upgrade my production servers as Those hangs would be > killers to my clients. Any ideas what this might be, or what to > investigate if it happens again? > Maybe login on a new session and then start with something simple like truss to attach to one of the hung processes and see what its doing and where it is ? Perhaps have a pcap running too on the outbound interface to see if the server processes are trying to send data out and its really the client thats locking up somehow ? (do an "echo hello | wall " and see if data gets sent on all the sessions). Increasing the verbosity of the sshd config to debug1 might shed some light too so you can see what the server process thinks is happening. Does your app write to a pty ? maybe it was hitting other pty sessions by accident ? ---Mike
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