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Date: Sat, 25 Jun 2005 00:50:20 -0400 (EDT)
From: Igor Pechtchanski <pechtcha AT cs DOT nyu DOT edu>
Reply-To: cygwin AT cygwin DOT com
To: cygwin AT cygwin DOT com
Subject: Re: Bash 3.0-2 and kill
In-Reply-To: <20050624223131.GA27592@trixie.casa.cgf.cx>
Message-ID: <Pine.GSO.4.61.0506250041120.18734@slinky.cs.nyu.edu>
References: <Pine DOT OSF DOT 4 DOT 21 DOT 0506242313310 DOT 4860-100000 AT ax0rm1 DOT roma1 DOT infn DOT it>  <Pine DOT GSO DOT 4 DOT 61 DOT 0506241732200 DOT 5118 AT slinky DOT cs DOT nyu DOT edu>  <20050624223131 DOT GA27592 AT trixie DOT casa DOT cgf DOT cx>
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On Fri, 24 Jun 2005, Christopher Faylor wrote:

> On Fri, Jun 24, 2005 at 05:38:02PM -0400, Igor Pechtchanski wrote:
> >On Fri, 24 Jun 2005, Angelo Graziosi wrote:
> >
> >> I have noted that when one uses
> >>
> >>    kill -9 <process-PID>
> >>
> >> in bash 3.0-2 (test), the command kills the process but also bash (even
> >> if one uses /bin/kill...).
> >>
> >> In bash 2.05b-17 that command kills only the process.
> >>
> >> These things happen with
> >>
> >>    cygwin 1.5.16-1
> >>    cygwin 1.5.17-1
> >>    snaps. 20050615
> >>    snaps. 20050617
> >>    snaps. 20050621
> >>
> >> (I have listed only the snaps I tried)
> >>
> >> Which is the normal behaviour (3.0-2 or 2.05b-17)?
> >
> >Unless the <process-PID> refers to the bash process itself, it seems that
> >the behavior of 3.0-2 is wrong.  Not sure if it's a bash bug, or a Cygwin
> >signal handling bug exposed by bash (the behavior of /bin/kill seems to
> >point toward the latter).
>
> Given that if cygwin was this broken all sorts of other things would be
> broken as well, this is more likely a problem with bash.

One reason for my guess was that I recalled discussions of bash using
pretty specialized spawn techniques, and it was likely to have some corner
case interaction with signal handling that normal programs wouldn't
encounter.  There may also be something different about the SIGCHLD that
bash is getting when the child is killed with SIGKILL.  But that was no
more than a guess, and yes, it's quite possible that there's a bug in the
bash signal handler.

> Running bash under zsh and trying a few kill -9's I finally got bash to
> exit with a "segmentation fault", which is more likely to be a problem
> with bash than with cygwin.

Fair enough.  I did ask the OP for the exact steps to reproduce the
problem, including the exact message he got from bash.  If he responds,
we'll see whether he saw the same symptoms you did.
	Igor
-- 
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ZZZzz /,`.-'`'    -.  ;-;;,_		igor AT watson DOT ibm DOT com
     |,4-  ) )-,_. ,\ (  `'-'		Igor Pechtchanski, Ph.D.
    '---''(_/--'  `-'\_) fL	a.k.a JaguaR-R-R-r-r-r-.-.-.  Meow!

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