CyberRota Analysis
AI-GeneratedThe vulnerability affects the Linux kernel's BTT (Block Translation Table) lanes, which manage access to per-lane metadata and workspace state during I/O operations. A race condition in lane acquisition can lead to silent data corruption during BTT writes, particularly when preemption occurs, allowing concurrent access to the same lane without proper locking. Organizations using Linux systems that rely on nvdimm functionality should prioritize addressing this issue to prevent potential data integrity problems.
Original NVD 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.