CVE-2026-72315
- Source
- https://cve.org/CVERecord?id=CVE-2026-72315
- Import Source
- https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-72315.json
- JSON Data
- https://api.osv.dev/v1/vulns/CVE-2026-72315
- Downstream
- Published
- 2026-08-15T05:55:29Z
- Modified
- 2026-10-08T02:51:47Z
- Severity
-
- 7.8 (High) CVSS_V3 - CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H CVSS Calculator
- Summary
- smb: client: fix busy dentry warning on unmount after DIO
- Details
-
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.
- Database specific
{ "cna_assigner": "Linux", "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72315.json" }- References
-
- https://git.kernel.org/stable/c/75f5c412fa867efa0bf9b646bffe0d912109e84a
- https://git.kernel.org/stable/c/9fc87899276af941ecf3045798887db7deb85605
- https://git.kernel.org/stable/c/f0eac9c3c3711f24efc2aaf12b8ec3e54a38c214
- https://git.kernel.org/stable/c/f7748b551010c021d92f0125e37f32ac0c376d8a
- https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/72xxx/CVE-2026-72315.json
- https://nvd.nist.gov/vuln/detail/CVE-2026-72315
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced0e4b8faaaebe3137bec5723ef2b3cb0437fb38fdFixedf7748b551010c021d92f0125e37f32ac0c376d8a
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedf655467a9973f964b267871e5fef533ad5014494Fixed9fc87899276af941ecf3045798887db7deb85605
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced340cea84f691c5206561bb2e0147158fe02070beFixedf0eac9c3c3711f24efc2aaf12b8ec3e54a38c214Fixed75f5c412fa867efa0bf9b646bffe0d912109e84a
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.12.78Fixed6.12.112
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.18.20Fixed6.18.54
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.1.167Fixed6.2
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.6.130Fixed6.7
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced6.19.10Fixed6.20
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced708c276f516d27beaded7f372ac8111cee43926c
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced0629a1a187e424373364d681b42b101894bdb548
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced30afc6ea72cc6cf7c8d579e79b64232801c38d08