From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <53320D1C.2050502@mail.com> Date: Wed, 26 Mar 2014 00:11:24 +0100 From: Adriano Verardo User-Agent: Mozilla/5.0 (Windows NT 6.1; rv:28.0) Gecko/20100101 Firefox/28.0 SeaMonkey/2.25 MIME-Version: 1.0 To: Fans of the OS Plan 9 from Bell Labs <9fans@9fans.net> References: <53311910.5090307@mail.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Subject: Re: [9fans] No regression tests Topicbox-Message-UUID: d02f0722-ead8-11e9-9d60-3106f5b1d025 erik quanstrom ha scritto: > On Tue Mar 25 01:51:36 EDT 2014, adriano.verardo@mail.com wrote: >> A few weeks ago i wrote about an unkillable manager of usb barcode >> readers. That code worked perfectly for 5+ years, with absolutely no >> changes. >> >> IMHO the problem seems to be a change in Bell kernel sources, as under >> 9Atom all works as expected. >> >> Unfortunately I can't say what is the last working release, because >> the problem has been noted for the first time some weeks ago, but the >> kernel is rebuilt frequently and the sources are upgraded, non >> regularly, 3/4 times in a year. > that's interesting. what state are these processes in what are > the backtraces? The task is basically a customized keyboard manager which open a channel in /srv. When running ps shows 4 instances, as it is started by usbd and forks 3 times. Unplugging the reader all four processes must (should) terminate. On Bell, since a while ago, only three die. Then, when plugging in again there is a spurious process which doesn't allow the other (new 4) to work. Kill nor slay works, the only solution is a reboot. Internal debug prints (#ifdef, no code changes) show exactly the same under Bell and Atom. In both cases, when unplugging, the manager notify the condition, notify it terminates but under Bell this doesn't actually happen. I regret not to have more detailed info. I suspect there is something changed in the detach primitives or so. But its only a very personal opinion. adriano