nfsd: clear CALLBACK_RUNNING on failed delegation recall queue
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.18.50, 7.2.4
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: nfsd: clear CALLBACK_RUNNING on failed delegation recall queue nfsd_break_one_deleg() sets NFSD4_CALLBACK_RUNNING via test_and_set_bit at entry to serialize recall work, then calls nfsd4_run_cb() to queue the recall. When the queue attempt fails the refcount bump is undone, but the RUNNING bit is left set. The only site that clears the bit is nfsd41_destroy_cb() (fs/nfsd/nfs4callback.c), which runs from the workqueue and is therefore unreachable when nothing was queued. The bit becomes a permanent latch on dp->dl_recall.cb_flags: every subsequent break_lease() on the same delegation hits the early-return guard in nfsd_break_one_deleg() and silently skips the recall, so the delegation is never broken and the conflicting open or lock stalls. Fix by clearing NFSD4_CALLBACK_RUNNING on the !queued branch alongside the refcount_dec.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From 1054e8ffc5c492f341bdf1888b882f1d163dd3d8 · fixed in b137930ee52e3ef38915a3511d4c070463b63a32; From 1054e8ffc5c492f341bdf1888b882f1d163dd3d8 · fixed in cb2d0c4d1b3d301d042ed61365eaa8cb0141a254; From 1054e8ffc5c492f341bdf1888b882f1d163dd3d8 · fixed in b036727d334b1b7cd4c1f1fba3b59ba93a6bbe96
- Linux Linux
6.15
- KernelLinux
From 6.15.0 · fixed in 6.18.50; From 6.19.0 · fixed in 7.2.4