Description

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

sched_ext: Replace rq_lock() to raw_spin_rq_lock() in scx_ops_bypass()

scx_ops_bypass() iterates all CPUs to re-enqueue all the scx tasks.
For each CPU, it acquires a lock using rq_lock() regardless of whether
a CPU is offline or the CPU is currently running a task in a higher
scheduler class (e.g., deadline). The rq_lock() is supposed to be used
for online CPUs, and the use of rq_lock() may trigger an unnecessary
warning in rq_pin_lock(). Therefore, replace rq_lock() to
raw_spin_rq_lock() in scx_ops_bypass().

Without this change, we observe the following warning:

===== START =====
[ 6.615205] rq->balance_callback && rq->balance_callback != &balance_push_callback
[ 6.615208] WARNING: CPU: 2 PID: 0 at kernel/sched/sched.h:1730 __schedule+0x1130/0x1c90
===== END =====

Classification

CVE ID: CVE-2025-21657

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.04% (probability of being exploited)

EPSS Percentile: 11.7% (scored less or equal to compared to others)

EPSS Date: 2025-02-19 (when was this score calculated)

References

https://git.kernel.org/stable/c/d9e446dd63cee7161717a6a8414ba9c6435af764
https://git.kernel.org/stable/c/6268d5bc10354fc2ab8d44a0cd3b042d49a0417e

Timeline