| From bippy-5f407fcff5a0 Mon Sep 17 00:00:00 2001 |
| From: Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
| To: <linux-cve-announce@vger.kernel.org> |
| Reply-to: <cve@kernel.org>, <linux-kernel@vger.kernel.org> |
| Subject: CVE-2025-21657: sched_ext: Replace rq_lock() to raw_spin_rq_lock() in scx_ops_bypass() |
| |
| 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 ===== |
| |
| The Linux kernel CVE team has assigned CVE-2025-21657 to this issue. |
| |
| |
| Affected and fixed versions |
| =========================== |
| |
| Issue introduced in 6.12 with commit 0e7ffff1b8117b05635c87d3c9099f6aa9c9b689 and fixed in 6.12.10 with commit d9e446dd63cee7161717a6a8414ba9c6435af764 |
| Issue introduced in 6.12 with commit 0e7ffff1b8117b05635c87d3c9099f6aa9c9b689 and fixed in 6.13 with commit 6268d5bc10354fc2ab8d44a0cd3b042d49a0417e |
| |
| Please see https://www.kernel.org for a full list of currently supported |
| kernel versions by the kernel community. |
| |
| Unaffected versions might change over time as fixes are backported to |
| older supported kernel versions. The official CVE entry at |
| https://cve.org/CVERecord/?id=CVE-2025-21657 |
| will be updated if fixes are backported, please check that for the most |
| up to date information about this issue. |
| |
| |
| Affected files |
| ============== |
| |
| The file(s) affected by this issue are: |
| kernel/sched/ext.c |
| |
| |
| Mitigation |
| ========== |
| |
| The Linux kernel CVE team recommends that you update to the latest |
| stable kernel version for this, and many other bugfixes. Individual |
| changes are never tested alone, but rather are part of a larger kernel |
| release. Cherry-picking individual commits is not recommended or |
| supported by the Linux kernel community at all. If however, updating to |
| the latest release is impossible, the individual changes to resolve this |
| issue can be found at these commits: |
| https://git.kernel.org/stable/c/d9e446dd63cee7161717a6a8414ba9c6435af764 |
| https://git.kernel.org/stable/c/6268d5bc10354fc2ab8d44a0cd3b042d49a0417e |
