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.
Published: 2026-10-06
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories

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History

Sat, 10 Oct 2026 03:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362

Sat, 10 Oct 2026 00:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-821
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Low


Wed, 07 Oct 2026 06:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362

Wed, 07 Oct 2026 04:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362

Tue, 06 Oct 2026 12:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362

Tue, 06 Oct 2026 09:00:00 +0000

Type Values Removed Values Added
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.
Title mm: filemap: retain mapped dropbehind folios
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-10-06T08:44:58.472Z

Reserved: 2026-09-25T10:25:14.327Z

Link: CVE-2026-98223

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-10-06T09:18:09.290

Modified: 2026-10-06T09:18:09.290

Link: CVE-2026-98223

cve-icon Redhat

Severity : Low

Publid Date: 2026-10-06T00:00:00Z

Links: CVE-2026-98223 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-10T04:30:17Z

Weaknesses
  • CWE-821

    Incorrect Synchronization