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Date: Sun, 10 Oct 2010 15:49:53 +0100
From: Al Viro <viro@ZenIV.linux.org.uk>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-m68k@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: aranym bug, manifests as "ida_remove called for id=13" on recent
 kernels
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On Sun, Oct 10, 2010 at 11:47:20AM +0200, Geert Uytterhoeven wrote:
> > The cheapest way to reproduce is to boot with init=/bin/sh, then
> > mount /proc and have stat("/proc/2/exe", &st) called; if stat()
> > returns 0, we are fscked. ??The critical part is between return
> > from proc_exe_link() (we'll leave it via if (!mm) return -ENOENT;)
> > to return from __do_follow_link() -> do_follow_link() -> link_path_walk().
> 
> I booted 2.6.36-rc7-atari-00360-g0dd2e6a (my current private test kernel) with
> init=/bin/sh, mounted /proc, and tried
> 
>     for i in $(seq 1000); do stat /proc/2/exe; done
> 
> a few times, but I didn't see any ida_remove messages.
> It cannot read the /proc/2/exe symlink, though.
> 
> This is on aranym-0.9.9-1 from Ubuntu/amd64.

stat -L /proc/2/exec, otherwise you'll hit lstat() instead of stat().
And FWIW 0.9.10-1 squeeze/amd64 also triggers here...