net/rds: Fix circular locking dependency in rds_tcp_tune
Affects the Linux kernel net/rds TCP transport in the rds_tcp_tune() path. Fixed in kernel 6.6.130, 6.12.77, 6.18.17 and 6.19.7 on their respective branches.
- 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- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean?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
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Unclear
- Fix
- Fixed in 5.18, 6.6.130, 6.12.77, 6.18.17, 6.19.7
- 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: net/rds: Fix circular locking dependency in rds_tcp_tune syzbot reported a circular locking dependency in rds_tcp_tune() where sk_net_refcnt_upgrade() is called while holding the socket lock: ====================================================== WARNING: possible circular locking dependency detected ====================================================== kworker/u10:8/15040 is trying to acquire lock: ffffffff8e9aaf80 (fs_reclaim){+.+.}-{0:0}, at: __kmalloc_cache_noprof+0x4b/0x6f0 but task is already holding lock: ffff88805a3c1ce0 (k-sk_lock-AF_INET6){+.+.}-{0:0}, at: rds_tcp_tune+0xd7/0x930 The issue occurs because sk_net_refcnt_upgrade() performs memory allocation (via get_net_track() -> ref_tracker_alloc()) while the socket lock is held, creating a circular dependency with fs_reclaim. Fix this by moving sk_net_refcnt_upgrade() outside the socket lock critical section. This is safe because the fields modified by the sk_net_refcnt_upgrade() call (sk_net_refcnt, ns_tracker) are not accessed by any concurrent code path at this point. v2: • Corrected fixes tag • check patch line wrap nits • ai commentary nits
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From 5.17.7 · fixed in 5.18
- Linux Linux
5.18
- KernelLinux
From 5.18.0 · fixed in 6.6.130; From 6.7.0 · fixed in 6.12.77; From 6.13.0 · fixed in 6.18.17; From 6.19.0 · fixed in 6.19.7
References 6
git.kernel.org
Questions about CVE-2026-23419
What does this mean?
The kernel's RDS TCP code in rds_tcp_tune() takes the socket lock and fs_reclaim in an order that can form a circular dependency, a lock-ordering deadlock risk. Syzbot reported it as a possible circular locking warning. The advisory does not describe any attacker-gained capability beyond this.Source: git.kernel.org
Am I affected, and how do I check?
The advisory lists Linux kernel versions 5.18.0 up to 6.6.130, 6.7.0 up to 6.12.77, 6.13.0 up to 6.18.17, and 6.19.0 up to 6.19.7, along with a Linux range starting at 5.17.7 and ending at 5.18. To check a system, run uname -r to see the kernel version, and run lsmod | grep rds to see whether the RDS module is loaded.Source: git.kernel.org
What should I do about it?
Upgrade to a kernel release that includes the fix for your branch: 6.6.130, 6.12.77, 6.18.17, or 6.19.7, or a later release in the same series.Source: git.kernel.org
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data