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Date:   Sat, 17 Apr 2021 03:42:17 +0000
From:   Al Viro <viro@zeniv.linux.org.uk>
To:     Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc:     davem@davemloft.net, daniel@iogearbox.net, andrii@kernel.org,
        netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH bpf-next 11/15] bpf: Add bpf_sys_close() helper.
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References: <20210417033224.8063-1-alexei.starovoitov@gmail.com>
 <20210417033224.8063-12-alexei.starovoitov@gmail.com>
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On Fri, Apr 16, 2021 at 08:32:20PM -0700, Alexei Starovoitov wrote:
> From: Alexei Starovoitov <ast@kernel.org>
> 
> Add bpf_sys_close() helper to be used by the syscall/loader program to close
> intermediate FDs and other cleanup.

Conditional NAK.  In a lot of contexts close_fd() is very much unsafe.
In particular, anything that might call it between fdget() and fdput()
is Right Fucking Out(tm).

In which contexts can that thing be executed?