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Improper Update of Reference Count The advisory has been revoked - it doesn't affect any version of package perf  (opens in a new tab)

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0.18% (7th percentile)

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  • Snyk IDSNYK-CENTOS10-PERF-18945081
  • published19 Aug 2026
  • disclosed15 Aug 2026
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Introduced: 15 Aug 2026

CVE-2026-72315  (opens in a new tab)
CWE-911  (opens in a new tab)

Amendment

The Centos security team deemed this advisory irrelevant for Centos:10.

NVD Description

Note: Versions mentioned in the description apply only to the upstream perf package and not the perf package as distributed by Centos.

In the Linux kernel, the following vulnerability has been resolved:

smb: client: fix busy dentry warning on unmount after DIO

Commit c68337442f03 ("cifs: Fix busy dentry used after unmounting") fixed the issue in cifs where deferred close of a file led to a dentry reference count not being released in umount, by flushing deferredclose_wq in cifs_kill_sb() to solve it.

However, the cifs DIO path suffers from the same busy-dentry problem caused by a delayed dentry reference-count release:

[dio]			[cifsd]			[close + umount]

netfs_unbuffered_write_iter_locked ... cifs_demultiplex_thread netfs_unbuffered_write cifs_issue_write netfs_wait_for_in_progress_stream [1] ... netfs_write_subrequest_terminated netfs_subreq_clear_in_progress netfs_wake_collector // wake [1] netfs_put_subrequest netfs_put_request queue_work(system_dfl_wq, xxx) [2] // dio write return cifs_close _cifsFileInfo_put // cfile->count 2->1 --cfile->count [3]

                        // umount
                        cifs_kill_sb
                         kill_anon_super
                          // warning triggered!
                          shrink_dcache_for_umount [4]

[system_dfl_wq] [5] netfs_free_request ... _cifsFileInfo_put // cfile->count 1->0 --cfile->count queue_work(fileinfo_put_wq, xxx)

[fileinfo_put_wq] [6] cifsFileInfo_put_work cifsFileInfo_put_final dput

If the umount path is triggered before [5], it results warning: BUG: Dentry 00000000eab1f070{i=9a917b66ae404fec,n=test} still in use (1) [unmount of cifs cifs]

The existing per-inode ictx->io_count wait in cifs_evict_inode() does not help: it lives in the inode eviction path, which runs after shrink_dcache_for_umount() has already warned about the busy dentries.

Fix it by adding a per-superblock outstanding-rreq counter that is incremented in cifs_init_request() and decremented in cifs_free_request(). In cifs_kill_sb(), before kill_anon_super(), wait for this counter to reach 0 - which guarantees that all cleanup_work for this sb have run and thus all relevant cfile puts are queued on fileinfo_put_wq or serverclose_wq. Then drain the workqueue so the dentry refs are dropped.

This is a targeted wait, not a flush of the system-wide system_dfl_wq.