Re: Kern/41566, Problem with pty(4) handling under NetBSD-5 filed.

[buhrow%lothlorien.nfbcal.org@localhost (Brian Buhrow)]

        Hello. I've not seen any responses on this message from anyone.  Is
there anyone who might be able to help me troubleshoot this problem?
I think I need to get down in the kernel and find out why things come to a
halt, but I'm not sure I understand things in there enough to find this
particular problem.  My test program is easy to run on any system, and so I
think the problem should be easily reproduced.  This bug turns out to be a
critical one for me, and I'm very interested in getting it fixed.  Any help
anyone might be able to offer would be greatly appreciated.

-thanks in advance.
-Brian

On Jun 10,  5:44am, Brian Buhrow wrote:
} Subject: Kern/41566, Problem with pty(4) handling under NetBSD-5 filed.
}       Hello.  Further investigation reveals a definite problem with the
} pty(4) code in NetBSD-5.  I've filed kern/41566 which contains a test
} program which demonstrates the problem.  The test program runs flawlessly
} under NetBSD-4 and earlier, but hangs the pty it uses very reliably under
} NetBSD-5.  I've tried this using the I386 platform; I've not yet tested
} other platforms to see if the problem is machine independent.
}       IF someone could look at this and shed some light on what might be
} going on, that would be great.
}       Here's what the test output looks like, for those who are curious.
} 
} -thanks
} -Brian
} 
} 
} 
} Script started on Wed Jun 10 00:25:44 2009
} %./ptytest&
} [1] 1756
} %./ptytest: Master process(1756) is writing to slave process (3339)
} ./ptytest: Using pty /dev/ttyp2
} 3339: Read 26 bytes from pty
} 3339: Read 2 bytes from pty
} 1756: Wrote 28 bytes to master pty
} 3339: Read 26 bytes from pty
} 3339: Read 2 bytes from pty
} 1756: Wrote 52 bytes to master pty
} 3339: Read 50 bytes from pty
} 3339: Read 2 bytes from pty
} 1756: Wrote 76 bytes to master pty
} 3339: Read 74 bytes from pty
} 3339: Read 2 bytes from pty
} 1756: Wrote 100 bytes to master pty
} 3339: Read 98 bytes from pty
} 3339: Read 2 bytes from pty
} 1756: Wrote 124 bytes to master pty
} 3339: Read 122 bytes from pty
} 3339: Read 2 bytes from pty
} 1756: Wrote 148 bytes to master pty
} 3339: Read 146 bytes from pty
} 3339: Read 2 bytes from pty
} 1756: Wrote 172 bytes to master pty
} 3339: Read 170 bytes from pty
} 3339: Read 2 bytes from pty
} 1756: Wrote 196 bytes to master pty
} 3339: Read 194 bytes from pty
} 3339: Read 2 bytes from pty
} 1756: Wrote 220 bytes to master pty
} 3339: Read 218 bytes from pty
} 3339: Read 2 bytes from pty
} 1756: Wrote 244 bytes to master pty
} 3339: Read 242 bytes from pty
} 3339: Read 2 bytes from pty
} 1756: Wrote 268 bytes to master pty
} 3339: Read 266 bytes from pty
} 1756: Wrote 28 bytes to master pty
} 1756: Wrote 52 bytes to master pty
} 1756: Wrote 76 bytes to master pty
} 1756: Wrote 100 bytes to master pty
} 1756: Wrote 124 bytes to master pty
} 1756: Wrote 148 bytes to master pty
} 1756: Wrote 172 bytes to master pty
} 1756: Wrote 196 bytes to master pty
} 3339: Read 2 bytes from pty
} 3339: Read 26 bytes from pty
} 3339: Read 2 bytes from pty
} 3339: Read 50 bytes from pty
} 3339: Read 2 bytes from pty
} 3339: Read 74 bytes from pty
} 3339: Read 2 bytes from pty
} 3339: Read 98 bytes from pty
} 3339: Read 2 bytes from pty
} 3339: Read 122 bytes from pty
} 3339: Read 2 bytes from pty
} 3339: Read 146 bytes from pty
} 3339: Read 2 bytes from pty
} 3339: Read 170 bytes from pty
} 3339: Read 2 bytes from pty
} 3339: Read 194 bytes from pty
} 3339: Read 2 bytes from pty
} 
} [Processes hang here, doing nothing]
} 
} ps -l1756
} UID  PID PPID CPU PRI NI  VSZ RSS WCHAN  STAT TTY      TIME COMMAND
} 100 1756 3460   0  85  0 2896 776 ttyraw S    ttyp1 0:00.01 ./ptytest 
} %ps -l3339
} UID  PID PPID CPU PRI NI  VSZ RSS WCHAN  STAT TTY      TIME COMMAND
} 100 3339 1756   0  85  0 2896 644 ttyraw S    ttyp1 0:00.00 ./ptytest 
} %
} %pstat -t |grep 'ttyp2'
} ttyp2   124  0 1024 1248 256     82 OC            0     0 termios
} %fg
} ./ptytest
} ^C
} %exit
} %exit
} 
} Script done on Wed Jun 10 00:27:23 2009
>-- End of excerpt from Brian Buhrow