CVE-2025-68356

gfs2: Prevent recursive memory reclaim

Published Dec 24, 2025 CVSS 3.1 · 5.5 Medium EPSS < 1% KEV · Not listed
Description
In the Linux kernel, the following vulnerability has been resolved:

gfs2: Prevent recursive memory reclaim

Function new_inode() returns a new inode with inode->i_mapping->gfp_mask
set to GFP_HIGHUSER_MOVABLE. This value includes the __GFP_FS flag, so
allocations in that address space can recurse into filesystem memory
reclaim. We don't want that to happen because it can consume a
significant amount of stack memory.

Worse than that is that it can also deadlock: for example, in several
places, gfs2_unstuff_dinode() is called inside filesystem transactions.
This calls filemap_grab_folio(), which can allocate a new folio, which
can trigger memory reclaim. If memory reclaim recurses into the
filesystem and starts another transaction, a deadlock will ensue.

To fix these kinds of problems, prevent memory reclaim from recursing
into filesystem code by making sure that the gfp_mask of inode address
spaces doesn't include __GFP_FS.

The "meta" and resource group address spaces were already using GFP_NOFS
as their gfp_mask (which doesn't include __GFP_FS). The default value
of GFP_HIGHUSER_MOVABLE is less restrictive than GFP_NOFS, though. To
avoid being overly limiting, use the default value and only knock off
the __GFP_FS flag. I'm not sure if this will actually make a
difference, but it also shouldn't hurt.

This patch is loosely based on commit ad22c7a043c2 ("xfs: prevent stack
overflows from page cache allocation").

Fixes xfstest generic/273.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Ubuntu USN Ubuntu USN USN-8094-1 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8094-2 Linux kernel vulnerabilities
Ubuntu USN Ubuntu USN USN-8094-3 Linux kernel (Real-time) vulnerabilities
Ubuntu USN Ubuntu USN USN-8094-4 Linux kernel (Azure) vulnerabilities
Ubuntu USN Ubuntu USN USN-8094-5 Linux kernel (Raspberry Pi) vulnerabilities
Ubuntu USN Ubuntu USN USN-8152-1 Linux kernel (OEM) vulnerabilities
History
Type Values Removed Values Added
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

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: gfs2: Prevent recursive memory reclaim Function new_inode() returns a new inode with inode->i_mapping->gfp_mask set to GFP_HIGHUSER_MOVABLE. This value includes the __GFP_FS flag, so allocations in that address space can recurse into filesystem memory reclaim. We don't want that to happen because it can consume a significant amount of stack memory. Worse than that is that it can also deadlock: for example, in several places, gfs2_unstuff_dinode() is called inside filesystem transactions. This calls filemap_grab_folio(), which can allocate a new folio, which can trigger memory reclaim. If memory reclaim recurses into the filesystem and starts another transaction, a deadlock will ensue. To fix these kinds of problems, prevent memory reclaim from recursing into filesystem code by making sure that the gfp_mask of inode address spaces doesn't include __GFP_FS. The "meta" and resource group address spaces were already using GFP_NOFS as their gfp_mask (which doesn't include __GFP_FS). The default value of GFP_HIGHUSER_MOVABLE is less restrictive than GFP_NOFS, though. To avoid being overly limiting, use the default value and only knock off the __GFP_FS flag. I'm not sure if this will actually make a difference, but it also shouldn't hurt. This patch is loosely based on commit ad22c7a043c2 ("xfs: prevent stack overflows from page cache allocation"). Fixes xfstest generic/273.
Title gfs2: Prevent recursive memory reclaim
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References
Weaknesses

No weakness.

Sources

Status
PUBLISHED
Assigner
Linux
Published
Updated
Oct 21, 2026, 12:38 PM
Reserved
Dec 16, 2025, 2:48 PM
Status
Deferred
Published
Dec 24, 2025, 11:15 AM
Modified
Oct 21, 2026, 1:18 PM
Severity
Low
Public date
Dec 24, 2025, 12:00 AM