CVE-2024-35929rcu/nocb: Fix WARN_ON_ONCE() in the rcu_nocb_bypass_lock()
- 7.8HighCVSS base score
- 0.22%Exploitation in 30 daysEPSS · top 87% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: rcu/nocb: Fix WARN_ON_ONCE() in the rcu_nocb_bypass_lock() For the kernels built with CONFIG_RCU_NOCB_CPU_DEFAULT_ALL=y and CONFIG_RCU_LAZY=y, the following scenarios will trigger WARN_ON_ONCE() in the rcu_nocb_bypass_lock() and rcu_nocb_wait_contended() functions: CPU2 CPU11 kthread rcu_nocb_cb_kthread ksys_write rcu_do_batch vfs_write rcu_torture_timer_cb proc_sys_write __kmem_cache_free proc_sys_call_handler kmemleak_free drop_caches_sysctl_handler delete_object_full drop_slab __delete_object shrink_slab put_object lazy_rcu_shrink_scan call_rcu rcu_nocb_flush_bypass __call_rcu_commn rcu_nocb_bypass_lock raw_spin_trylock(&rdp->nocb_bypass_lock) fail atomic_inc(&rdp->nocb_lock_contended); rcu_nocb_wait_contended WARN_ON_ONCE(smp_processor_id() != rdp->cpu); WARN_ON_ONCE(atomic_read(&rdp->nocb_lock_contended)) | |_ _ _ _ _ _ _ _ _ _same rdp and rdp->cpu != 11_ _ _ _ _ _ _ _ _ __| Reproduce this bug with "echo 3 > /proc/sys/vm/drop_caches". This commit therefore uses rcu_nocb_try_flush_bypass() instead of rcu_nocb_flush_bypass() in lazy_rcu_shrink_scan(). If the nocb_bypass queue is being flushed, then rcu_nocb_try_flush_bypass will return directly.
Timeline
ID reserved
By Linux
- 2 days later
· 2 days later
Published
- 24 months later
· 24 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| NVDNVD · Analyzed | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.22% · top 87% of all CVEs (14 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
- affected 7625926086765123251f765d91fc3a70617d334d – < 4d58c9fb45c70e62c19e8be3f3605889c47601bc
- affected 7625926086765123251f765d91fc3a70617d334d – < 927d1f4f77e4784ab3944a9df86ab14d1cd3185a
- affected 7625926086765123251f765d91fc3a70617d334d – < dda98810b552fc6bf650f4270edeebdc2f28bd3f
- affected 6.5
- unaffected < 6.5
- unaffected 6.6.27 – ≤ 6.6.*
- unaffected 6.8.6 – ≤ 6.8.*
- unaffected 6.9 – ≤ *
References
References3
- https://git.kernel.org/stable/c/4d58c9fb45c70e62c19e8be3f3605889c47601bc (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/927d1f4f77e4784ab3944a9df86ab14d1cd3185a (opens in a new tab)x_transferred
- https://git.kernel.org/stable/c/dda98810b552fc6bf650f4270edeebdc2f28bd3f (opens in a new tab)x_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2024-35647 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2024-35929)Record last updated .