cbcvebase.
CVE-2025-38338
published 2025-07-10

CVE-2025-38338: 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…

PriorityP338high7.8CVSS 3.1
AVLACLPRLUINSUCHIHAH
EPSS
0.16%
5.3th percentile
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: netfs_read_collection_worker+0x67/0x80 process_one_work+0x12e/0x2c0 worker_thread+0x295/0x3a0 Most of the time, however, processes just get stuck forever in folio_wait_bit_common(), waiting for `PG_locked` to disappear, which never happens because nobody is really holding the folio lock.

Affected

23 ranges
VendorProductVersion rangeFixed in
debianlinux< linux 6.12.35-1 (forky)linux 6.12.35-1 (forky)
linuxlinux
linuxlinux>= 000dbe0bec058cbf2ca9e156e4a5584f5158b0f9 < 14f5549ad163be2c018abc1bb38370fff617a24314f5549ad163be2c018abc1bb38370fff617a243
linuxlinux>= 000dbe0bec058cbf2ca9e156e4a5584f5158b0f9 < 5bf0b9eeb0174686f22c2e5b8fb9f47ad25da6f55bf0b9eeb0174686f22c2e5b8fb9f47ad25da6f5
linuxlinux>= 000dbe0bec058cbf2ca9e156e4a5584f5158b0f9 < 1e93b61d3eaa14bfebcc2716ac09d43f3845d4201e93b61d3eaa14bfebcc2716ac09d43f3845d420
linuxlinux>= 000dbe0bec058cbf2ca9e156e4a5584f5158b0f9 < 4c10fa44bc5f700e2ea21de2fbae520ba21f19d94c10fa44bc5f700e2ea21de2fbae520ba21f19d9
linuxlinux_kernel>= 0 < 6.12.35-16.12.35-1
linuxlinux_kernel>= 0 < 6.12.35-16.12.35-1
linuxlinux_kernel>= 0 < 6.8.0-100.1006.8.0-100.100
linuxlinux_kernel>= 6.13 < 6.15.46.15.4
linuxlinux_kernel>= 6.4 < 6.6.956.6.95
linuxlinux_kernel>= 6.7 < 6.12.356.12.35
msrcazl3_kernel_6.6.92.2-2_on_azure_linux_3.0
msrcazl3_kernel_6.6.96.1-1_on_azure_linux_3.0
ubuntulinux-aws
ubuntulinux-aws-6.8
ubuntulinux-gkeop
ubuntulinux-nvidia
ubuntulinux-nvidia-6.8
ubuntulinux-oracle
ubuntulinux-oracle-6.8
ubuntulinux-raspi-realtime
ubuntulinux-realtime

CVSS provenance

nvdv3.17.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
osv7.8HIGH
vendor_debian7.8LOW
vendor_msrc7.8HIGH
vendor_redhat7.8HIGH
vendor_ubuntu5.6MEDIUM
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