CVE-2026-97521
Received Received - Intake

GFS2 Quota Init Race Condition Fix

Publication date: 2026-09-24

Last updated on: 2026-09-24

Assigner: kernel.org

Description
In the Linux kernel, the following vulnerability has been resolved: gfs2: fix quota init duplicate scan gfs2_quota_init() checks for duplicate quota_change IDs while holding qd_lock and the quota hash bucket bitlock. That path used gfs2_qd_search_bucket(), which takes a lockref reference via lockref_get_not_dead(). On PREEMPT_RT this may sleep, which is not allowed under the bucket bitlock, triggering "sleeping function called from invalid context". Use a no-ref bucket lookup in this path, then continue duplicate handling without taking a lockref there. Refactor gfs2_qd_search_bucket() to build on top of the no-ref helper so lookup traversal stays in one place. This patch fixes a bug reported by syzbot.

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Meta Information

Published
2026-09-24
Last Modified
2026-09-24
Generated
2026-09-24
AI Q&A
2026-09-24
EPSS Evaluated
N/A
NVD
CVE-2026-97521
EUVD
EUVD-2026-86119

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

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KEV
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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel involves a race condition in the GFS2 file system's quota initialization. The function gfs2_quota_init() checks for duplicate quota IDs while holding locks, but on PREEMPT_RT systems, a function called lockref_get_not_dead() may sleep, which violates the locking context and causes a kernel error.

Detection Guidance

This vulnerability is specific to the Linux kernel's GFS2 filesystem quota initialization. Detection requires checking kernel logs for 'sleeping function called from invalid context' errors related to gfs2_quota_init. Use commands like 'dmesg | grep -i gfs2' or 'journalctl -k | grep -i gfs2' to search for relevant errors.

Impact Analysis

This vulnerability could cause system instability or crashes on Linux systems using GFS2 with PREEMPT_RT enabled. It may lead to kernel panics or unexpected reboots when quota initialization occurs.

Mitigation Strategies

Apply the kernel patch that resolves this issue. Update your Linux kernel to a version containing the fix for gfs2_quota_init duplicate scan. Monitor kernel logs for any related errors after applying the patch.

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