Bug 2562660 (CVE-2026-99132)

Summary: CVE-2026-99132 kernel: kernel: Denial of Service via deadlock in XFS superblock buffer synchronization
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone: ---Keywords: Security
Target Release: ---   
Hardware: All   
OS: Linux   
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Doc Text:
A flaw was found in the Linux kernel's XFS file system. A local attacker could cause a Denial of Service (DoS) by triggering a deadlock during file system metadata synchronization. Under specific conditions, such as a file system shutdown during a synchronous transaction commit, held buffer locks prevent background worker processes from completing cleanup, resulting in a complete system hang.
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
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Description OSIDB Bzimport 2026-10-28 10:45:24 UTC 
In the Linux kernel, the following vulnerability has been resolved:

xfs: don't hold buffer locks across sync transaction commit in xfs_sync_sb_buf

xfs_sync_sb_buf() holds sb/rtsb buffer locks across a synchronous
xfs_trans_commit(), which flushes the CIL push workqueue internally.
If shutdown occurs during the CIL push, xfs_buf_item_unpin() needs to
lock these buffers to fail them, causing a deadlock:

  setlabel:          holds buf lock -> flush_workqueue(xfs-cil)
  CIL push worker:   xfs_buf_item_unpin -> xfs_buf_lock(same buf)

Remove the xfs_trans_bhold() calls so that commit releases the buffer
locks normally.  After the sync commit, re-acquire the buffers via
mp->m_sb_bp / mp->m_rtsb_bp for the on-disk writeback.