CVE-2026-99132xfs: don't hold buffer locks across sync transaction commit in xfs_sync_sb_buf

Official description

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.

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/16468281da17263095bd1906cf2d16a972f10791
• https://git.kernel.org/stable/c/45f124f3902bfae6a366d124db04f707264176fb
• https://git.kernel.org/stable/c/d900946853c2d183fa0e199bae9ddbcd21795a18
• https://git.kernel.org/stable/c/83b2e511cf9ba22904b167e00fcbd85169b50b2c
• https://git.kernel.org/stable/c/acd7f2f9b822b6e126f3e3c99c173e62aa315b6f
• https://git.kernel.org/stable/c/e5456dec79c71c8ef8f9f9adb77d320f113b34db
• https://git.kernel.org/stable/c/6353e5cd8c43d6e805cacbfbfecf4103571a7ff8
• https://git.kernel.org/stable/c/41a28c865d1d5843f8cb9e0af17a8f4d9e2961ff