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[2001:1c00:2a07:3a01:8e96:3679:b9c:de47]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c296614323csm94042566b.59.2026.09.11.08.23.40 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 11 Sep 2026 08:23:40 -0700 (PDT) From: Hans de Goede To: Bjorn Andersson , Cristian Marussi , Sudeep Holla Cc: Hans de Goede , Daniel Lezcano , Bjorn Andersson , Frank.Li@kernel.org, arm-scmi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-arm-msm@vger.kernel.org, imx@lists.linux.dev, linux-kernel@vger.kernel.org Subject: [PATCH v6 3/4] firmware: arm_scmi: Fix scmi_protocol_device_unrequest() race Date: Fri, 11 Sep 2026 17:23:28 +0200 Message-ID: <20260911152329.5822-4-johannes.goede@oss.qualcomm.com> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260911152329.5822-1-johannes.goede@oss.qualcomm.com> References: <20260911152329.5822-1-johannes.goede@oss.qualcomm.com> 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-Proofpoint-GUID: 2qV8uD_w6nXIanFVAkUnuex1_bBNtzih X-Authority-Analysis: v=2.4 cv=PLmaavqC c=1 sm=1 tr=0 ts=6aa41d01 cx=c_pps a=DUEm7b3gzWu7BqY5nP7+9g==:117 a=xqWC_Br6kY4A:10 a=VdqzKS8jKosA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=rJkE3RaqiGZ5pbrm-msn:22 a=EUspDBNiAAAA:8 a=EzzhlMzFHTv8R9URApkA:9 a=-aSRE8QhW-JAV6biHavz:22 X-Proofpoint-ORIG-GUID: 2qV8uD_w6nXIanFVAkUnuex1_bBNtzih X-Proofpoint-Spam-Info: AW1haW4tMjYwOTExMDIxNCBTYWx0ZWRfX4m4O2MTe6WKM 16DfTQm7Pz5J1UkU5SFGttVud0Vq9eqMudC/t2PMS1Ld765YbOdiKh9BbdG+CHhmdAI80XUNPcR Xu6EEdo8sqT8mgmAlMjdECfCXCcOR30= X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTExMDIxNCBTYWx0ZWRfX1DyuQFRjHCPs dIKSrUeOvKfpefEtzwsBond+0fWQxIqvt546Ng6ezO+Br96HztiZ+y64vn0cr6iE4+hoNgkjbB9 PTm2vxrt6UPYXOAnYf8PeXjN4zv9VpAKBhE26SC93XvG5Rv2d0enjJ/tti9H3YApj0krPYskcjN 9Q1gGf2JkhTXJL/xM6WbU68Z/OvZxnvYlSfHX6lOAcle+cBA9x9/hwJ0UCjgJOiG/TGUr6HFRw5 cAwAE+IsawIzoplLGqc3l0PXrNvqLJlhlojsARg30CJ1Z5h84/+7aqvcuIiLUZoifU7Uf1E1P1l gibxoyeuKz7NSfHjJ/7hQsc7tEFvliIBDfpe82vkdysnf6CrWEBibx+UpAecs/QrpgLDYSS3Z42 979px624SgjxMba/5HIBPLU6isHcxE5qw7/s/W9e/A7aRBUT1ipbvSNxuwo9JyYrioakhkkGVQ3 DDqHESUZwpPgvLhEM/w== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-09-11_05,2026-09-11_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 bulkscore=0 suspectscore=0 spamscore=0 phishscore=0 adultscore=0 malwarescore=0 clxscore=1015 priorityscore=1501 impostorscore=0 lowpriorityscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2609110214 scmi_protocol_device_unrequest() unlocks scmi_requested_devices_mtx during the notifier call. During this window phead might have been deleted by another racing scmi_protocol_device_unrequest(). Re-acquire phead before cleaning it up to avoid this potential double free problem. Fixes: d3cd7c525fd2 ("firmware: arm_scmi: Refactor protocol device creation") Signed-off-by: Hans de Goede --- Changes in v6: - New patch in v6 of this series (Suggested by local Shashiko run on v5) --- drivers/firmware/arm_scmi/bus.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/arm_scmi/bus.c b/drivers/firmware/arm_scmi/bus.c index 6f667e4ffeed..651d4ba06574 100644 --- a/drivers/firmware/arm_scmi/bus.c +++ b/drivers/firmware/arm_scmi/bus.c @@ -173,7 +173,13 @@ static void scmi_protocol_device_unrequest(const struct scmi_device_id *id_table } } - if (list_empty(phead)) { + /* + * Since scmi_requested_devices_mtx is unlocked during + * the notifier call phead might have been deleted by another + * racing scmi_protocol_device_unrequest(), re-acquire it here. + */ + phead = idr_find(&scmi_requested_devices, id_table->protocol_id); + if (phead && list_empty(phead)) { idr_remove(&scmi_requested_devices, id_table->protocol_id); kfree(phead); -- 2.55.0