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Date: Tue, 15 Aug 2006 14:22:25 -0700
From: Andrew Morton <akpm@osdl.org>
To: Andi Kleen <ak@suse.de>
Cc: linux-kernel@vger.kernel.org
Subject: Re: [PATCH] [2/3] Create call_usermodehelper_pipe()
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On Mon, 14 Aug 2006 13:27:31 +0200 (CEST)
Andi Kleen <ak@suse.de> wrote:

> +	/* Install input pipe when needed */
> +	if (sub_info->stdin) {
> +		struct files_struct *f = current->files;
> +		struct fdtable *fdt;
> +		/* no races because files should be private here */
> +		sys_close(0);
> +		fd_install(0, sub_info->stdin);
> +		spin_lock(&f->file_lock);
> +		fdt = files_fdtable(f);
> +		FD_SET(0, fdt->open_fds);
> +		FD_CLR(0, fdt->close_on_exec);
> +		spin_unlock(&f->file_lock);
> +	}

This is all going to be run by kernel threads, and all kernel threads share
current->files=&init_files.

So I suspect that if two coredumps happen at the same time bad things will
happen.  Like a BUG() in fd_install()?