CVE-2025-21900

NFSv4: Fix a deadlock when recovering state on a sillyrenamed file

State: Published
Severity: 7.5 High
Published: Apr 1, 2025
Updated: Aug 5, 2026
Reserved: Dec 29, 2024

Description

In the Linux kernel, the following vulnerability has been resolved:

NFSv4: Fix a deadlock when recovering state on a sillyrenamed file

If the file is sillyrenamed, and slated for delete on close, it is possible for a server reboot to triggeer an open reclaim, with can again race with the application call to close(). When that happens, the call to put_nfs_open_context() can trigger a synchronous delegreturn call which deadlocks because it is not marked as privileged.

Instead, ensure that the call to nfs4_inode_return_delegation_on_close() catches the delegreturn, and schedules it asynchronously.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H	Linux
3.1	5.5 Medium	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H	CISA-ADP

Weaknesses

CWE-667 Improper Locking

Affected Products

Product	Versions
LinuxLinux	adb4b42d19aea91826621a8d0bac94cf2c08f8bc to before 4fe4ae6c2e01d028856b73b6328b12b8945df871Affected adb4b42d19aea91826621a8d0bac94cf2c08f8bc to before f41a60bc43e7abbc636fee78bed0d74c31e738b0Affected adb4b42d19aea91826621a8d0bac94cf2c08f8bc to before 8f8df955f078e1a023ee55161935000a67651f38Affected
LinuxLinux	6.11Affected before 6.11Not affected 6.12.18 through 6.12.Not affected 6.13.6 through 6.13.Not affected 6.14 and laterNot affected

References

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