* [Xenomai-core] rt_pipe_open / rt_pipe_delete bug @ 2010-06-03 8:09 stephane ancelot 2010-06-03 14:35 ` Andreas Glatz 0 siblings, 1 reply; 4+ messages in thread From: stephane ancelot @ 2010-06-03 8:09 UTC (permalink / raw) To: xenomai Hi, tryied in v2.4.10 : I have opened a /dev/rtp7 pipe , and deleted it. if I launch again the same program, rt_pipe_open replies with -EBUSY .... Best Regards S.Ancelot ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Xenomai-core] rt_pipe_open / rt_pipe_delete bug 2010-06-03 8:09 [Xenomai-core] rt_pipe_open / rt_pipe_delete bug stephane ancelot @ 2010-06-03 14:35 ` Andreas Glatz 2010-06-14 14:52 ` stephane ancelot 0 siblings, 1 reply; 4+ messages in thread From: Andreas Glatz @ 2010-06-03 14:35 UTC (permalink / raw) To: stephane ancelot; +Cc: xenomai On Thu, Jun 03, 2010 at 04:09:38AM -0400, stephane ancelot wrote: > Hi, > > tryied in v2.4.10 : > > > I have opened a /dev/rtp7 pipe , and deleted it. > > if I launch again the same program, rt_pipe_open replies with -EBUSY .... > Can you describe the sequence how you are invoking rt_pipe_open()/open()/rt_pipe_delete()? If the following description applies to you then you discovered what we've discovered before and there is no easy fix for that as far as I know. 1) create pipe with rt_pipe_open() 2) connect to it by opening /dev/rtp7 with open() 3) delete pipe with rt_pipe_delete() (for example by killing the Xenomai application) 4) create same pipe again with rt_pipe_open() (for example by restarting the Xenomai application with /dev/rtp7 is still open) --> rt_pipe_open() reports an error Andreas ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Xenomai-core] rt_pipe_open / rt_pipe_delete bug 2010-06-03 14:35 ` Andreas Glatz @ 2010-06-14 14:52 ` stephane ancelot 2010-06-14 16:08 ` Philippe Gerum 0 siblings, 1 reply; 4+ messages in thread From: stephane ancelot @ 2010-06-14 14:52 UTC (permalink / raw) To: Andreas Glatz; +Cc: xenomai H Le Thu, 03 Jun 2010 16:35:50 +0200, Andreas Glatz <andreasglatz@domain.hid> a écrit: > On Thu, Jun 03, 2010 at 04:09:38AM -0400, stephane ancelot wrote: >> Hi, >> >> tryied in v2.4.10 : >> >> >> I have opened a /dev/rtp7 pipe , and deleted it. >> >> if I launch again the same program, rt_pipe_open replies with -EBUSY >> .... >> > > Can you describe the sequence how you are invoking > rt_pipe_open()/open()/rt_pipe_delete()? > > If the following description applies to you then you discovered what > we've discovered > before and there is no easy fix for that as far as I know. > > 1) create pipe with rt_pipe_open() > 2) connect to it by opening /dev/rtp7 with open() > 3) delete pipe with rt_pipe_delete() (for example by killing the Xenomai > application) > 4) create same pipe again with rt_pipe_open() (for example by restarting > the > Xenomai application with /dev/rtp7 is still open) > > --> rt_pipe_open() reports an error > Yes, but it has worked in xeno 2.1 .... Is there a work around ? only hacking it ? Best Regards S.Ancelot > Andreas ^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [Xenomai-core] rt_pipe_open / rt_pipe_delete bug 2010-06-14 14:52 ` stephane ancelot @ 2010-06-14 16:08 ` Philippe Gerum 0 siblings, 0 replies; 4+ messages in thread From: Philippe Gerum @ 2010-06-14 16:08 UTC (permalink / raw) To: stephane ancelot; +Cc: xenomai On Mon, 2010-06-14 at 16:52 +0200, stephane ancelot wrote: > H > Le Thu, 03 Jun 2010 16:35:50 +0200, Andreas Glatz > <andreasglatz@domain.hid> a écrit: > > > On Thu, Jun 03, 2010 at 04:09:38AM -0400, stephane ancelot wrote: > >> Hi, > >> > >> tryied in v2.4.10 : > >> > >> > >> I have opened a /dev/rtp7 pipe , and deleted it. > >> > >> if I launch again the same program, rt_pipe_open replies with -EBUSY > >> .... > >> > > > > Can you describe the sequence how you are invoking > > rt_pipe_open()/open()/rt_pipe_delete()? > > > > If the following description applies to you then you discovered what > > we've discovered > > before and there is no easy fix for that as far as I know. > > > > 1) create pipe with rt_pipe_open() > > 2) connect to it by opening /dev/rtp7 with open() > > 3) delete pipe with rt_pipe_delete() (for example by killing the Xenomai > > application) > > 4) create same pipe again with rt_pipe_open() (for example by restarting > > the > > Xenomai application with /dev/rtp7 is still open) > > > > --> rt_pipe_open() reports an error > > > > Yes, but it has worked in xeno 2.1 .... 2.1 was utterly broken wrt pipe session handling, it did not work, at all. It just created opportunities to trash your kernel memory badly upon rt-side closure, by allowing userland to work on a deallocated pipe while in a race window. Now both ends are in sync, and the rt-pipe is allowed to linger until userland is really done with it, i.e. when it has closed its endpoint. You will get -EBUSY on the rt-side until that point is reached. > Is there a work around ? only > hacking it ? Fix your app on the userland side. It should receive a zero-length read upon rt-side closure. You just need to check for this, then close this endpoint and reopen it right after if need be. > Best Regards > S.Ancelot > > > Andreas > > _______________________________________________ > Xenomai-core mailing list > Xenomai-core@domain.hid > https://mail.gna.org/listinfo/xenomai-core -- Philippe. ^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2010-06-14 16:08 UTC | newest] Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2010-06-03 8:09 [Xenomai-core] rt_pipe_open / rt_pipe_delete bug stephane ancelot 2010-06-03 14:35 ` Andreas Glatz 2010-06-14 14:52 ` stephane ancelot 2010-06-14 16:08 ` Philippe Gerum
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