CVE-2026-23374

/// Technical description

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

blktrace: fix __this_cpu_read/write in preemptible context

tracing_record_cmdline() internally uses __this_cpu_read() and

__this_cpu_write() on the per-CPU variable trace_cmdline_save, and

trace_save_cmdline() explicitly asserts preemption is disabled via

lockdep_assert_preemption_disabled(). These operations are only safe

when preemption is off, as they were designed to be called from the

scheduler context (probe_wakeup_sched_switch() / probe_wakeup()).

__blk_add_trace() was calling tracing_record_cmdline(current) early in

the blk_tracer path, before ring buffer reservation, from process

context where preemption is fully enabled. This triggers the following

using blktests/blktrace/002:

blktrace/002 (blktrace ftrace corruption with sysfs trace) [failed]

runtime 0.367s ... 0.437s

something found in dmesg:

[ 81.211018] run blktests blktrace/002 at 2026-02-25 22:24:33

[ 81.239580] null_blk: di

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References