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Subject: Re: [PATCH] UML: Use PTRACE_KILL instead of SIGKILL to kill
	host-OS processes
From: Anton Altaparmakov <aia21@cam.ac.uk>
To: Chris Wedgwood <cw@f00f.org>
Cc: Jeff Dike <jdike@addtoit.com>, Blaisorblade <blaisorblade_spam@yahoo.it>,
       user-mode-linux-devel@lists.sourceforge.net,
       Andrew Morton <akpm@osdl.org>, lkml <linux-kernel@vger.kernel.org>
In-Reply-To: <20041103113736.GA23041@taniwha.stupidest.org>
References: <20041103113736.GA23041@taniwha.stupidest.org>
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Organization: University of Cambridge Computing Service, UK
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On Wed, 2004-11-03 at 11:37, Chris Wedgwood wrote:
> kill(..., SIGKILL) doesn't work to kill host-OS processes created in
> the exec path in TT mode --- for this we need PTRACE_KILL (it did work
> in previous kernels, but not by design).  Without this process will
> accumulate on the host-OS (although the won't be visible inside UML).
> 
> Signed-off-by: Chris Wedgwood <cw@f00f.org>
> ---
> 
> Yes, there are other fixes along these lines which are needed but one
> at a time as we test these...
> 
> Index: cw-current/arch/um/kernel/tt/exec_user.c
> ===================================================================
> --- cw-current.orig/arch/um/kernel/tt/exec_user.c	2004-11-03 02:10:18.064830204 -0800
> +++ cw-current/arch/um/kernel/tt/exec_user.c	2004-11-03 02:12:10.447716745 -0800
> @@ -35,7 +35,8 @@
>  		tracer_panic("do_exec failed to get registers - errno = %d",
>  			     errno);
>  
> -	kill(old_pid, SIGKILL);
> +	if (ptrace(PTRACE_KILL, old_pid, NULL, NULL))
> +		printk("Warning: ptrace(PTRACE_KILL, %d, ...) saw %d\n", errno);

You have two %d but only one argument.  You seem to have forgotten an
"old_pid, " in there.

>  
>  	if(ptrace_setregs(new_pid, regs) < 0)
>  		tracer_panic("do_exec failed to start new proc - errno = %d",

Best regards,

	Anton
-- 
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK
Linux NTFS maintainer / IRC: #ntfs on irc.freenode.net
WWW: http://linux-ntfs.sf.net/, http://www-stu.christs.cam.ac.uk/~aia21/

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