From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-cve-announce@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@kernel.org>
Subject: CVE-2026-98223: mm: filemap: retain mapped dropbehind folios
Date: Tue, 6 Oct 2026 10:45:24 +0200 [thread overview]
Message-ID: <2026100643-CVE-2026-98223-b511@gregkh> (raw)
From: Greg Kroah-Hartman <gregkh@kernel.org>
Description
===========
In the Linux kernel, the following vulnerability has been resolved:
mm: filemap: retain mapped dropbehind folios
Fault-around can map ready dropbehind folios without going through the
normal page-cache lookup that clears dropbehind. A mapping represents a
competing cached user, so retain the folio instead of forcibly unmapping
it when writeback completes.
For a mapped folio, folio_unmap_invalidate() can call
unmap_mapping_folio(), which takes i_mmap_rwsem and may sleep. Retaining
mapped folios avoids this path when folio_end_dropbehind() runs in
non-preemptible task context.
Tal was able to trigger a sleeping-in-atomic warning due to this [1].
Unmapped dropbehind folios continue through the existing invalidation path.
The Linux kernel CVE team has assigned CVE-2026-98223 to this issue.
Affected and fixed versions
===========================
Issue introduced in 6.14 with commit fb7d3bc4149395c1ae99029c852eab6c28fc3c88 and fixed in 6.18.54 with commit 2897601dffe576fcd87a4259102f41f7fb0cbfc8
Issue introduced in 6.14 with commit fb7d3bc4149395c1ae99029c852eab6c28fc3c88 and fixed in 7.2.8 with commit 77c0fade37c80e8aa16ac048a9828249055e3f66
Issue introduced in 6.14 with commit fb7d3bc4149395c1ae99029c852eab6c28fc3c88 and fixed in 7.3-rc4 with commit 848d2ce2fce15fbdc083fbf9691bfa72911033c4
Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.
Unaffected versions might change over time as fixes are backported to
older supported kernel versions. The official CVE entry at
https://cve.org/CVERecord/?id=CVE-2026-98223
will be updated if fixes are backported, please check that for the most
up to date information about this issue.
Affected files
==============
The file(s) affected by this issue are:
mm/filemap.c
Mitigation
==========
The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes. Individual
changes are never tested alone, but rather are part of a larger kernel
release. Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all. If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
https://git.kernel.org/stable/c/2897601dffe576fcd87a4259102f41f7fb0cbfc8
https://git.kernel.org/stable/c/77c0fade37c80e8aa16ac048a9828249055e3f66
https://git.kernel.org/stable/c/848d2ce2fce15fbdc083fbf9691bfa72911033c4
reply other threads:[~2026-10-06 10:24 UTC|newest]
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