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Date:   Mon, 22 Mar 2021 07:53:10 +0000
From:   Christoph Hellwig <hch@infradead.org>
To:     Andy Lutomirski <luto@kernel.org>
Cc:     Alexey Dobriyan <adobriyan@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux API <linux-api@vger.kernel.org>
Subject: Re: [PATCH] Document that PF_KTHREAD _is_ ABI
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On Sat, Mar 20, 2021 at 10:23:12AM -0700, Andy Lutomirski wrote:
> > https://github.com/systemd/systemd/blob/main/src/basic/process-util.c#L354
> > src/basic/process-util.c:is_kernel_thread()
> 
> Eww.
> 
> Could we fix it differently and more permanently by modifying the proc
> code to display the values systemd expects?

Yes, do_task_stat needs a mapping from kernel flags to UABI flags.  And
we should already discard everything we think we can from the UABI
now, and only add the ones back that are required to not break
userspace.