linux-kernel - Re: umount -l <path>, getcwd and /proc/<pid>/cwd inconsistent

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Message-ID: <4781E301.7000502@xs4all.nl>
Date:	Mon, 07 Jan 2008 09:29:53 +0100
From:	Bauke Jan Douma <bjdouma@...all.nl>
To:	Ian Kent <raven@...maw.net>
CC:	linux-kernel@...r.kernel.org
Subject: Re: umount -l <path>, getcwd and /proc/<pid>/cwd inconsistent

Ian Kent wrote on 07-01-08 04:17:
> Hi all,
> 
> Could someone please help me understand what's happening with, what
> looks like inconsistent behavior, between getpwd and procfs readlink.
> 
> Basically, from a bash shell, setting working directory to a mounted
> directory all is fine with "pwd" and "/proc/<pid>/cwd". Following a
> "umount - l" on the mount "pwd" continues to return the expected string
> but "/proc/<pid>/cwd" returns an empty string.
> 
> What I'm really after is why this happens because sys_getcwd and
> proc_pid_readlink appear to do essentially the same thing to get the
> string.
> 
[snip]

What does `/bin/pwd' return, when you do that instead of
plain `pwd' (after the umount)?

bjd


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