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Date:   Fri, 18 Sep 2020 17:16:15 +0200
From:   Christoph Hellwig <hch@lst.de>
To:     Al Viro <viro@zeniv.linux.org.uk>
Cc:     Christoph Hellwig <hch@lst.de>,
        Andrew Morton <akpm@linux-foundation.org>,
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Subject: Re: [PATCH 1/9] kernel: add a PF_FORCE_COMPAT flag
Message-ID: <20200918151615.GA23432@lst.de>
References: <20200918124533.3487701-1-hch@lst.de> <20200918124533.3487701-2-hch@lst.de> <20200918134012.GY3421308@ZenIV.linux.org.uk> <20200918134406.GA17064@lst.de> <20200918135822.GZ3421308@ZenIV.linux.org.uk>
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On Fri, Sep 18, 2020 at 02:58:22PM +0100, Al Viro wrote:
> Said that, why not provide a variant that would take an explicit
> "is it compat" argument and use it there?  And have the normal
> one pass in_compat_syscall() to that...

That would help to not introduce a regression with this series yes.
But it wouldn't fix existing bugs when io_uring is used to access
read or write methods that use in_compat_syscall().  One example that
I recently ran into is drivers/scsi/sg.c.