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Date:   Thu, 6 Oct 2022 13:33:31 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     ira.weiny@intel.com
Cc:     "Fabio M. De Francesco" <fmdefrancesco@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Christoph Hellwig <hch@lst.de>,
        kernel test robot <lkp@intel.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Linus Walleij <linus.walleij@linaro.org>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2] highmem: Fix kmap_to_page() for kmap_local_page()
 addresses
Message-Id: <20221006133331.dabd345508f7d62a887dfb4d@linux-foundation.org>
In-Reply-To: <20221006040555.1502679-1-ira.weiny@intel.com>
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On Wed,  5 Oct 2022 21:05:55 -0700 ira.weiny@intel.com wrote:

> kmap_to_page() is used to get the page for a virtual address which may
> be kmap'ed.  Unfortunately, kmap_local_page() stores mappings in a
> thread local array separate from kmap().  These mappings were not
> checked by the call.
> 
> Check the kmap_local_page() mappings and return the page if found.
> 
> Because it is intended to remove kmap_to_page() add a warn on once to
> the kmap checks to flag potential issues early.

What were the user-visible runtime effects of this?

Are we able to identify a Fixes:?

Thanks.