Terminal Deadlock When TTY Buffer Full

[bonefish]

r24356

The Terminal can deadlock when the tty buffer runs full. Attached is a KDL session analyzing the situation. In short:

• Window thread: Is in Shell::Write() writing to the TTY, blocking because the TTY buffer is full.
• PtyReader thread: Is in TermParse::PtyReader(), blocking on fReaderLocker.
• EscParse thread: Is in TermView::_Redraw(), blocking trying to lock the window.

May or may not be related to #1755. I can't unblock the Terminal by resizing/zooming the window, though, so it probably isn't.

Regarding how to reproduce it: I have seen this only once yet. I suppose it helps to have a command line program that prints a lot and type something at the same time.

[bonefish]

Just verified the way to reproduce the bug: "seq 100000" + hammering on the keyboard seems to be reliable.

[thorn]

looks like fixed. I can't reproduce with "seq 100000"

[anevilyak]

Possibly related to this, I noticed tail -f on syslog while doing a Haiku build goes dead after a while, no user interaction needed though.

[mmlr]

The tail -f probably just ends because the syslog is full and a new syslog file is created. You should try tail -F instead as this will reopen the new syslog and follow it when it is exchanged.

[anevilyak]

What's the size limit on syslog? It hadn't shown more than maybe 20-30 lines before it stopped. Also ctrl+c to terminate tail didn't work at that point.

[mmlr]

The limit doesn't really matter, if it was 90% full it might have been exchanged after only a few new lines. But that you couldn't ctrl-c it would obviously be a bug.

[bonefish]

Fixed in r25881. At least the original problem. If the syslog issue still exists (and actually was a problem), please open a new ticket.