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Mon, 16 Feb 2026 18:50:06 +0000 (GMT) From: Aboorva Devarajan To: rafael@kernel.org, christian.loehle@arm.com, daniel.lezcano@linaro.org Cc: aboorvad@linux.ibm.com, linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 0/4] cpuidle: Fix crash with single idle state Date: Tue, 17 Feb 2026 00:20:01 +0530 Message-ID: <20260216185005.1131593-1-aboorvad@linux.ibm.com> X-Mailer: git-send-email 2.52.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: JLOgnF3_C8jcX7mqtfnmMk8s8zEphQyC X-Authority-Analysis: v=2.4 cv=Md9hep/f c=1 sm=1 tr=0 ts=699366e3 cx=c_pps a=GFwsV6G8L6GxiO2Y/PsHdQ==:117 a=GFwsV6G8L6GxiO2Y/PsHdQ==:17 a=HzLeVaNsDn8A:10 a=VkNPw1HP01LnGYTKEx00:22 a=Mpw57Om8IfrbqaoTuvik:22 a=GgsMoib0sEa3-_RKJdDe:22 a=VwQbUJbxAAAA:8 a=VnNF1IyMAAAA:8 a=8cvJxYw84IpXfcRceYoA:9 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwMjE2MDE1OSBTYWx0ZWRfXxOkyB/TaDzJl UCqcqNcYHHDMjbbBO2Fs3SncH8sOXusMJ2G/rQp3aiecIgu8Koi8DyPHDX05++4npy3ck3sG6Z3 94bDn0F1UiYephyAwyf2Ev4lMMjUS9t85VehutX1wN8PcqiJa22dk8cfjKa2O5iY3CSSPCt8ya5 OTwTTvqkoyCaF5DzBmkafT8SV0wGcSzbzH7w6RRxJ5Bl12B1w22CV4WX6Pprbxvgiymv1Jg05Ak dd7xDR5Bg/OMboflkEmLuaY9dQhHZrP0gC1l4n/hW8HdIS5mP9DWApHYmoAYiaFz+eQ3F80DFq/ +Bwr0V23C0FNfZPKpe3oNjzqnbLJyd/EEpYVxiFnB92hdz3KvuuFmk584DdZsu5F+cxCAbdSmQm I//glMjGdPqJ0ZnIufUFQlVAkmALIYQe7Kof5To4wxhQ7LDVLcpwDMvS6k8ikVbe3tT/BiOFM/5 R8lbUjGuaMwRawQFEGA== X-Proofpoint-GUID: JLOgnF3_C8jcX7mqtfnmMk8s8zEphQyC X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1121,Hydra:6.1.51,FMLib:17.12.100.49 definitions=2026-02-16_06,2026-02-16_04,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 clxscore=1015 impostorscore=0 lowpriorityscore=0 spamscore=0 adultscore=0 priorityscore=1501 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2601150000 definitions=main-2602160159 When a cpuidle driver registers only a single idle state, the ladder governor can compute an out-of-bounds index, leading to a NULL pointer dereference in cpuidle_enter_state(). Patch 1 fixes this by adding a bail-out in cpuidle_select() that bypasses the governor entirely when state_count <= 1. Patches 2-4 remove the now-redundant single-state handling from the haltpoll, teo, and menu governors. v1: https://lore.kernel.org/all/20260211053552.739337-1-aboorvad@linux.ibm.com/ v1 -> v2: - Move fix to cpuidle_select() core bail-out instead of ladder governor - Remove redundant single-state handling from menu, teo, haltpoll Aboorva Devarajan (2): cpuidle: Skip governor when only one idle state is available cpuidle: haltpoll: Remove single state handling Christian Loehle (2): cpuidle: teo: Remove single state handling cpuidle: menu: Remove single state handling drivers/cpuidle/cpuidle.c | 10 ++++++++++ drivers/cpuidle/governors/haltpoll.c | 2 +- drivers/cpuidle/governors/menu.c | 2 +- drivers/cpuidle/governors/teo.c | 6 ------ 4 files changed, 12 insertions(+), 8 deletions(-) -- 2.52.0