CVE-2026-89567: In the Linux kernel, the following vulnerability has been resolved: jbd2: bound shrinker scans by examined checkpoint b
Summary
A bug in the Linux kernel's jbd2 (a journaling system for file operations) shrinker was causing it to scan checkpoint buffers (temporary storage for transaction data) without properly limiting how many it examines, leading to lock contention (when multiple processors compete for the same resource) and system hangs. The fix ensures that the shrinker counts all examined buffers, not just successfully released ones, against its scan budget to prevent excessive lock hold times.
Solution / Mitigation
Pass nr_to_scan (the number of items to examine) into journal_shrink_one_cp_list() and decrement it for every buffer examined, including busy buffers. Pass NULL from checkpoint cleanup paths to preserve their existing full-list behavior. This restores the scan-budget semantics that existed before the function was changed to always scan a complete checkpoint list.
Vulnerability Details
EPSS: 0.0%
September 11, 2026
Classification
Original source: https://nvd.nist.gov/vuln/detail/CVE-2026-89567
First tracked: September 11, 2026 at 08:07 PM
Classified by LLM (prompt v3) · confidence: 95%