Executive brief
A vulnerability was identified in the Linux kernel's Btrfs file system where certain diagnostic monitoring tools could cause the system to crash or behave unexpectedly. This occurs because the system attempts to perform a 'sleep' operation during a task that must be completed without interruption. An exploit could lead to a system hang or a kernel panic, impacting the availability of the server.
Technical details
A 'sleep while in atomic context' vulnerability exists in the btrfs_sync_file() tracepoint of the Linux kernel. Trace events execute in an atomic context where sleeping is prohibited; however, the implementation previously called dget_parent() and dput(), the latter of which can trigger a sleep. This mismatch results in a kernel splat (BUG: sleeping function called from invalid context). The fix involves replacing the reference-counted parent dentry access with direct access via dentry->d_parent to avoid the sleeping dput() call. Patches have been released across multiple stable kernel branches.
Affected products
- Linux Linux kernel btrfs file system component
Timeline
- 2026-04-28: patched: Initial fix authored
- 2026-07-19: advisory: CVE published
References
- https://git.kernel.org/stable/c/0a96d9a85cd2240481297156b9bb72e10b7a8036
- https://git.kernel.org/stable/c/12a0487945c09760a5968d9333383014ea294117
- https://git.kernel.org/stable/c/26b2290baaf6da6add0f782a100766e686a33f4f
- https://git.kernel.org/stable/c/4361954f0e158af0530caa1e57f12b531be4658f
- https://git.kernel.org/stable/c/6279992c9ba2774901c9d4dd4a481162e2534714
- https://git.kernel.org/stable/c/c32a7e0e3c73c1c0768556a56bd78de9f7b83780
- https://git.kernel.org/stable/c/c73370c677646e86fc4b1780fb07027bdf847375