[Freeswitch-users] failed to wait for I/O

Tue Nov 16 20:42:25 PST 2010

That is good enough. I committed a patch that should fix it, try git pull
please.

Moises Silva
Senior Software Engineer
Sangoma Technologies Inc. | 100 Renfrew Drive, Suite 100, Markham ON L3R 9R6
Canada
t. 1 905 474 1990 x128 | e. moy at sangoma.com

On Sun, Nov 14, 2010 at 7:10 PM, Troy Anderson <
freeswitch at tlainvestments.com> wrote:

> I've been looking deeper into this, and it seems that poll() in zt_wait
> ftmod_zt.c is returning EINTR, which means it was interrupted by a signal
> while in the system call (as the error points out).  After STFW for a while,
> the advice is to immediately call poll() again if receiving an EINTR.  I
> would patch the code and try it, but the only place I'm experiencing this is
> in a busy installation, and I don't want to risk the downtime before getting
> some feedback as the the viability of such an approach.
>
> In addition, I am not familiar enough with linux signals to be sure this is
> a good idea.  Is there a way to find out what signal is interrupting the
> system call?  That may be helpful in determining what's going on here.
>
> Here's the patch I'm considering:
>
> --- a/libs/freetdm/src/ftmod/ftmod_zt/ftmod_zt.c
> +++ b/libs/freetdm/src/ftmod/ftmod_zt/ftmod_zt.c
> @@ -885,7 +885,8 @@ static FIO_WAIT_FUNCTION(zt_wait)
>        memset(&pfds[0], 0, sizeof(pfds[0]));
>        pfds[0].fd = ftdmchan->sockfd;
>        pfds[0].events = inflags;
> -       result = poll(pfds, 1, to);
> +       while ((result = poll(pfds, 1, to)) < 0 && errno == EINTR)
> +    continue;
>        *flags = 0;
>
>        if (pfds[0].revents & POLLERR) {
>
> Any thoughts?
>
> Thanks,
> Troy
>
> On Nov 12, 2010, at 10:26 AM, Anthony Minessale wrote:
>
> > sigh, another case of DAHDI issues.
> >
> >
> > On Fri, Nov 12, 2010 at 10:25 AM, Troy Anderson
> > <freeswitch at tlainvestments.com> wrote:
> >> Thanks for the code change providing additional diagnostics.  I finally
> saw another call drop, but didn't have full logging on at the time.  The
> additional logging provided the following:
> >>
> >> 2010-11-12 11:12:54.906656 [ERR] ftmod_zt.c:904 [s1c23][1:23] Failed to
> poll DAHDI device: Interrupted system call
> >> 2010-11-12 11:12:54.906656 [ERR] ftmod_zt.c:904 [s1c19][1:19] Failed to
> poll DAHDI device: Interrupted system call
> >> 2010-11-12 11:12:54.906656 [WARNING] mod_freetdm.c:660 failed to wait
> for I/O
> >> 2010-11-12 11:12:54.906656 [WARNING] mod_freetdm.c:660 failed to wait
> for I/O
> >> 2010-11-12 11:12:54.906656 [ERR] ftmod_zt.c:904 [s1c20][1:20] Failed to
> poll DAHDI device: Interrupted system call
> >> 2010-11-12 11:12:54.906656 [WARNING] mod_freetdm.c:660 failed to wait
> for I/O
> >> 2010-11-12 11:12:54.906656 [ERR] ftmod_zt.c:904 [s1c21][1:21] Failed to
> poll DAHDI device: Interrupted system call
> >> 2010-11-12 11:12:54.906656 [WARNING] mod_freetdm.c:660 failed to wait
> for I/O
> >>
> >> I'll turn up logging and see what shows up next time, but any ideas on
> what may cause this?
> >>
> >> Thanks!
> >> Troy
> >>
> >> On Nov 6, 2010, at 2:17 PM, Moises Silva wrote:
> >>
> >>> On Fri, Nov 5, 2010 at 12:58 PM, Troy Anderson
> >>> <freeswitch at tlainvestments.com> wrote:
> >>>> We have an installation with a dual PRI and lots of call volume.
>  Among many successful calls each day, we have been experiencing a one or
> two dropped per day, and they always coincide with a "failed to wait for
> I/O" warning from mod_freetdm.  I have attempted to track down the root
> cause in the source and by poring over the logs, but cannot figure it out.
>  I have included the redacted logs here.  The log file in question is 10MB
> and has lots of call data that doesn't relate - I know I risked removing
> something important, but I tried to put in all the data related to this
> call.
> >>>>
> >>>> I appreciate any insights or advice on tracking this down.
> >>>>
> >>>
> >>> If you update your git tree you will be able to get more information
> >>> the next time it happens. I added some code to print the reason for
> >>> that error to happen.
> >>>
> >>> Moises Silva
> >>> Senior Software Engineer
> >>> Sangoma Technologies Inc. | 100 Renfrew Drive, Suite 100, Markham ON
> >>> L3R 9R6 Canada
> >>> t. 1 905 474 1990 x128 | e. moy at sangoma.com
> >>>
> >>> _______________________________________________
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> >
> >
> >
> > --
> > Anthony Minessale II
> >
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