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

nvdimm/btt: Handle preemption in BTT lane acquisition

BTT lanes serialize access to per-lane metadata and workspace state
during BTT I/O. The btt-check unit test reports data mismatches during
BTT writes due to a race in lane acquisition that can lead to silent
data corruption.

The existing lane model uses a spinlock together with a per-CPU
recursion count. That recursion model stopped being valid after BTT
lanes became preemptible: another task can run on the same CPU,
observe a non-zero recursion count, bypass locking, and use the same
lane concurrently.

BTT lanes are also held across arena_write_bytes() calls. That path
reaches nsio_rw_bytes(), which flushes writes with nvdimm_flush().
Some provider flush callbacks can sleep, making a spinlock the wrong
primitive for the lane lifetime.

Replace the spinlock-based recursion model with a dynamically
allocated per-lane mutex array and take the lane lock
unconditionally.

Add might_sleep() to catch any future atomic-context caller.

Found with the ndctl unit test btt-check.sh.
Published: 2026-08-15
Score: n/a
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

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History

Sat, 15 Aug 2026 16:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362

Sat, 15 Aug 2026 06:15:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: nvdimm/btt: Handle preemption in BTT lane acquisition BTT lanes serialize access to per-lane metadata and workspace state during BTT I/O. The btt-check unit test reports data mismatches during BTT writes due to a race in lane acquisition that can lead to silent data corruption. The existing lane model uses a spinlock together with a per-CPU recursion count. That recursion model stopped being valid after BTT lanes became preemptible: another task can run on the same CPU, observe a non-zero recursion count, bypass locking, and use the same lane concurrently. BTT lanes are also held across arena_write_bytes() calls. That path reaches nsio_rw_bytes(), which flushes writes with nvdimm_flush(). Some provider flush callbacks can sleep, making a spinlock the wrong primitive for the lane lifetime. Replace the spinlock-based recursion model with a dynamically allocated per-lane mutex array and take the lane lock unconditionally. Add might_sleep() to catch any future atomic-context caller. Found with the ndctl unit test btt-check.sh.
Title nvdimm/btt: Handle preemption in BTT lane acquisition
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-15T05:58:47.594Z

Reserved: 2026-08-15T05:44:03.888Z

Link: CVE-2026-74365

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-15T06:22:38.143

Modified: 2026-08-15T06:22:38.143

Link: CVE-2026-74365

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-08-15T16:30:03Z

Weaknesses
  • CWE-362

    Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')