Release Date: | 2025-07-10 | |
Impact: | Moderate | What is this? |
In the Linux kernel, the following vulnerability has been resolved:
fs/nfs/read: fix double-unlock bug in nfs_return_empty_folio()
Sometimes, when a file was read while it was being truncated by
another NFS client, the kernel could deadlock because folio_unlock()
was called twice, and the second call would XOR back the `PG_locked`
flag.
Most of the time (depending on the timing of the truncation), nobody
notices the problem because folio_unlock() gets called three times,
which flips `PG_locked` back off:
1. vfs_read, nfs_read_folio, ... nfs_read_add_folio,
nfs_return_empty_folio
2. vfs_read, nfs_read_folio, ... netfs_read_collection,
netfs_unlock_abandoned_read_pages
3. vfs_read, ... nfs_do_read_folio, nfs_read_add_folio,
nfs_return_empty_folio
The problem is that nfs_read_add_folio() is not supposed to unlock the
folio if fscache is enabled, and a nfs_netfs_folio_unlock() check is
missing in nfs_return_empty_folio().
Rarely this leads to a warning in netfs_read_collection():
------------[ cut here ]------------
R=0000031c: folio 10 is not locked
WARNING: CPU: 0 PID: 29 at fs/netfs/read_collect.c:133 netfs_read_collection+0x7c0/0xf00
[...]
Workqueue: events_unbound netfs_read_collection_worker
RIP: 0010:netfs_read_collection+0x7c0/0xf00
[...]
Call Trace:
See more information about CVE-2025-38338 from MITRE CVE dictionary and NIST NVD
NOTE: The following CVSS metrics and score provided are preliminary and subject to review.
Base Score: | 5.5 |
Vector String: | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
Version: | 3.1 |
Attack Vector: | Local |
Attack Complexity: | Low |
Privileges Required: | Low |
User Interaction: | None |
Scope: | Unchanged |
Confidentiality Impact: | None |
Integrity Impact: | None |
Availability Impact: | High |
Platform | Errata | Release Date |
Oracle Linux version 10 (kernel-uek) | ELSA-2025-20551 | 2025-09-08 |
Oracle Linux version 9 (kernel-uek) | ELSA-2025-20551 | 2025-09-08 |
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