CVE-2024-50121
nfsd: cancel nfsd_shrinker_work using sync mode in nfs4_state_shutdown_net
- State
- Published
- Severity
- 7.8 High
- Published
- Nov 5, 2024
- Updated
- Oct 15, 2026
- Reserved
- Oct 21, 2024
Description
In the Linux kernel, the following vulnerability has been resolved:
nfsd: cancel nfsd_shrinker_work using sync mode in nfs4_state_shutdown_net
In the normal case, when we excute `echo 0 > /proc/fs/nfsd/threads`, the function `nfs4_state_destroy_net` in `nfs4_state_shutdown_net` will release all resources related to the hashed `nfs4_client`. If the `nfsd_client_shrinker` is running concurrently, the `expire_client` function will first unhash this client and then destroy it. This can lead to the following warning. Additionally, numerous use-after-free errors may occur as well.
nfsd_client_shrinker echo 0 > /proc/fs/nfsd/threads
expire_client nfsd_shutdown_net unhash_client ... nfs4_state_shutdown_net /* won't wait shrinker exit */ /* cancel_work(&nn->nfsd_shrinker_work) * nfsd_file for this /* won't destroy unhashed client1 */ * client1 still alive nfs4_state_destroy_net */
nfsd_file_cache_shutdown /* trigger warning */ kmem_cache_destroy(nfsd_file_slab) kmem_cache_destroy(nfsd_file_mark_slab) /* release nfsd_file and mark */ __destroy_client
==================================================================== BUG nfsd_file (Not tainted): Objects remaining in nfsd_file on __kmem_cache_shutdown() -------------------------------------------------------------------- CPU: 4 UID: 0 PID: 764 Comm: sh Not tainted 6.12.0-rc3+ #1
dump_stack_lvl+0x53/0x70 slab_err+0xb0/0xf0 __kmem_cache_shutdown+0x15c/0x310 kmem_cache_destroy+0x66/0x160 nfsd_file_cache_shutdown+0xac/0x210 [nfsd] nfsd_destroy_serv+0x251/0x2a0 [nfsd] nfsd_svc+0x125/0x1e0 [nfsd] write_threads+0x16a/0x2a0 [nfsd] nfsctl_transaction_write+0x74/0xa0 [nfsd] vfs_write+0x1a5/0x6d0 ksys_write+0xc1/0x160 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e
==================================================================== BUG nfsd_file_mark (Tainted: G B W ): Objects remaining nfsd_file_mark on __kmem_cache_shutdown() --------------------------------------------------------------------
dump_stack_lvl+0x53/0x70 slab_err+0xb0/0xf0 __kmem_cache_shutdown+0x15c/0x310 kmem_cache_destroy+0x66/0x160 nfsd_file_cache_shutdown+0xc8/0x210 [nfsd] nfsd_destroy_serv+0x251/0x2a0 [nfsd] nfsd_svc+0x125/0x1e0 [nfsd] write_threads+0x16a/0x2a0 [nfsd] nfsctl_transaction_write+0x74/0xa0 [nfsd] vfs_write+0x1a5/0x6d0 ksys_write+0xc1/0x160 do_syscall_64+0x5f/0x170 entry_SYSCALL_64_after_hwframe+0x76/0x7e
To resolve this issue, cancel `nfsd_shrinker_work` using synchronous mode in nfs4_state_shutdown_net.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.8 High | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H | CISA-ADP |
Weaknesses
- CWE-416 Use After Free
Affected Products
| Product | Versions |
|---|---|
LinuxLinux |
|
LinuxLinux |
|
References
- https://git.kernel.org/stable/c/f67138dd338cb564ade7d3755c8cd4f68b46d397
- https://git.kernel.org/stable/c/5ade4382de16c34d9259cb548f36ec5c4555913c
- https://git.kernel.org/stable/c/36775f42e039b01d4abe8998bf66771a37d3cdcc
- https://git.kernel.org/stable/c/f965dc0f099a54fca100acf6909abe52d0c85328
- https://git.kernel.org/stable/c/add1df5eba163a3a6ece11cb85890e2e410baaea
- https://git.kernel.org/stable/c/d5ff2fb2e7167e9483846e34148e60c0c016a1f6
- https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html
- https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html
- https://cert-portal.siemens.com/productcert/html/ssa-265688.html
Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.