Re: [hylafax-users] modem (or faxgetty?) hangs "receiving from ..." STRACE AND LOG

[Aidan Van Dyk <aidan@xxxxxxxx>]

* Lee Howard <faxguy@xxxxxxxxxxxxxxxx> [031208 11:02]:

> On 2003.12.08 07:28 Patrick Fromberg wrote:
> 
> >Dec 08 15:02:27.55: [ 5284]: RECV: 15208 bytes of data, 556 total 
> >lines
> >Dec 08 15:02:27.55: [ 5284]: awaiting characters from the modem - 
> >will timeout in 180000 ms
> >Dec 08 15:02:27.55: [ 5284]: no longer awaiting modem response
> >Dec 08 15:02:27.55: [ 5284]: --> [16:+FPS:1,233,0,0,0]
> 
> >Dec 08 15:02:39.82: [ 5284]: RECV: 14569 bytes of data, 554 total 
> >lines
> >Dec 08 16:01:56.72: [ 5284]: awaiting characters from the modem - 
> >will timeout in 180000 ms
> >Dec 08 16:01:56.72: [ 5284]: no longer awaiting modem response
> >Dec 08 16:01:56.72: [ 5284]: --> [16:+FPS:1,231,0,0,0]
> 
> >Dec 08 16:01:56.82: [ 5284]: <-- [7:AT+FDR\r]
> >Dec 08 16:01:56.82: [ 5284]: awaiting characters from the modem - 
> >will timeout in 180000 ms
> >Dec 08 16:01:56.82: [ 5284]: no longer awaiting modem response
> >Dec 08 16:01:56.82: [ 5284]: --> [7:+FHS:A0]
> >Dec 08 16:01:56.82: [ 5284]: REMOTE HANGUP: Unspecified Phase D error 
> >(code A0)
> 
> Although this session did end due to some kind of modem firmware error, 
> it did not "hang" as it has in previous logs you have shown, so you're 
> going to need to give us a log of a session where it does "hang".

It did hang.  It hung for an hour, until he put the strace on it,

	Dec 08 15:02:31.30: [ 5284]: RECV: send trigger 022
	Dec 08 15:02:31.30: [ 5284]: <-- data [1]
	Dec 08 15:02:39.82: [ 5284]: RECV: 14569 bytes of data, 554 total lines

Hang is here.  After a while, he attaches strace to it:

	16:01:56.727457 rt_sigaction(SIGALRM, {0x400a0b10, [], SA_RESTORER|SA_INTERRUPT, 0x4029a5c8}, NULL, 8) = 0
	16:01:56.727711 setitimer(ITIMER_REAL, {it_interval={0, 0}, it_value={180, 0}}, NULL) = 0

Which interrupts whichever syscall was "blocking" it, and faxgetty
continues on.  Unfortunately, the action of attaching the process
unblocked whatever syscall was happening.

	Dec 08 16:01:56.72: [ 5284]: awaiting characters from the modem - will timeout in 180000 ms
	Dec 08 16:01:56.72: [ 5284]: no longer awaiting modem response
	Dec 08 16:01:56.72: [ 5284]: --> [16:+FPS:1,231,0,0,0]
	Dec 08 16:01:56.82: [ 5284]: <-- [7:AT+FDR\r]
	Dec 08 16:01:56.82: [ 5284]: awaiting characters from the modem - will timeout in 180000 ms
	Dec 08 16:01:56.82: [ 5284]: no longer awaiting modem response
	Dec 08 16:01:56.82: [ 5284]: --> [7:+FHS:A0]
	Dec 08 16:01:56.82: [ 5284]: REMOTE HANGUP: Unspecified Phase D error (code A0)

> As for this error (+FHS:A0), only Elsa can fix it for you since they 
> control the firmware.

The protocol error would make sense, seeing as it was read and responded
to some 59 minutes after the modem issued it.

Patrick,

Would it be able to have an strace of the life of faxgetty before the
hang?  If you can attach strace to it before faxgetty hangs, when it
hangs, we should be able to what was happening just before the hang too.

a.

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