[prev in list] [next in list] [prev in thread] [next in thread] 

List:       linux-kernel
Subject:    Re: [PATCHSET] ptrace,signal: group stop / ptrace updates
From:       Ingo Molnar <mingo () elte ! hu>
Date:       2011-01-28 16:54:55
Message-ID: 20110128165455.GA18194 () elte ! hu
[Download RAW message or body]


Hi,

I'm hijacking this thread, to report a signal handling bug that Linux and Bash has, 
and which has been there at least for 10 years since i started using SMP Linux 
systems ...

It's not easy to reproduce but today i found a reproducer - maybe you guys have an 
idea what's going on.

There's two very simple scripts, one calls the other in an infinite loop:

 $ cat test-signal
 #!/bin/bash

 while true; do ./test-signal2; done

 $ cat test-signal2
 #!/bin/bash

 true

The bug is that occasionally Ctrl-C does not get processed, and that the Ctrl-C is 
'lost'. It can be reproduced here by running ./test-signal several times, and 
Ctrl-C-ing it:

 $ ./test-signal
 ^C
 $ ./test-signal
 ^C^C
 $ ./test-signal
 ^C

See that '^C^C' line? That is where i had to do Ctrl-C twice.

It only fails here about once every 10 times, so it's very rare. I have a stock F14 
system running on that box, with the very latest .38 based kernel.

Any ideas what's going on?

Thanks,

	Ingo
--
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/
[prev in list] [next in list] [prev in thread] [next in thread]