Messages in this thread | | | Date | Sat, 25 Oct 2003 22:48:50 -0700 (PDT) | From | Linus Torvalds <> | Subject | Re: Linux 2.6.0-test9 |
| |
On Sun, 26 Oct 2003 Andries.Brouwer@cwi.nl wrote: > > I have run 2.6.0-test6 without any problems. Switched > to 2.6.0-test9 today. Something involving job control > or so is broken. Several of my remote xterms hang.
Btw, this one sounds like a known bug in bash.
The bash bug does bad things when setting up pipelines of processes, and it assigns the process groups in the wrong order. This causes the tty layer to send SIGTTOU if the process touches the tty at just the right time, which in turn causes processes to become stuck in STOPPED state. It's very timing sensitive, and it apparently became easier to trigger within the last month or so, probably because of the scheduler interactivity changes.
You can trigger it under 2.4.x, and in fact it seems to be reasonably easy to see with
while true ; do date | less -E ; done
which will cause processes to become stuck in stopped state after a while (but because of the timing issues it's not 100% repeatable - you may have to do this for a while).
You can work around it by building basb without the "PGRP_PIPE" config option (which may cause other issues), but Ernie Petrides also had a proper fix for it in the bash sources. Last I say (this was end of September), Chet Ramey acknowledged the bug but hadn't yet put it in standard bash sources.
It's definitely not a kernel bug. I chased it for a while myself, and Ernie proved it quite conclusively.
Linus
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |