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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> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Authority-Analysis: v=2.4 cv=d6lgWhjE c=1 sm=1 tr=0 ts=6aa41d01 cx=c_pps a=N1BjEkVkxJi3uNfLdpvX3g==:117 a=xqWC_Br6kY4A:10 a=VdqzKS8jKosA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=3WHJM1ZQz_JShphwDgj5:22 a=EUspDBNiAAAA:8 a=EzzhlMzFHTv8R9URApkA:9 a=crWF4MFLhNY0qMRaF8an:22 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwOTExMDIxNCBTYWx0ZWRfXz9gS57N9vPWG UzK9oMAi2tv/m+gzQ7D35e7FS1i1bmkep0imoU/7yIHaKA44yZW6O/jwnLMIKg5XQEu94nK5UW0 Www4n1BKrk10XFiIlGjY8koOgPsVFf3Pj57ATDTg8iyfp22rL3PQWAoxcAGUQpCyCmi/zy7baup nOLY6MypTXjnxubm0IsM9C57jZ73zZDZr2Ekxmzsi9QbRt46JbSTJ2YjJJV392qxzFlICG8B0Eu 2duwciJIHatrmPahUaY+Soai7gPsnKm0d6mD/KZXBU5281XXoUxpEo77cXhDSnHgFTjGs7dQ1od D+sDsDT1A0I1VyfdwJtz/DaFjsko5dyHFSMv428LegF4FhFVUnLTEdfX+brFAFjVQU1K247lY+J ynjypM/0WAVrSVYgY9MW07EfhaL/prBLvUM6yTFM6p2o1aoKpcY4yUU/ZVW5je5bK2s7wkwdkU9 dRYpFNdDNwqsMesGM9g== X-Proofpoint-Spam-Info: AW1haW4tMjYwOTExMDIxNCBTYWx0ZWRfXxbtlDohPwiAD 8EhHrOLeg9FvYqSapjpxAeZ84LvO0mOLdCXfVeZJMwCp8Pkv0fgRqDMYyP8IFgnkJvIB10WKeoj N5VEGE+vD3ISF3GqOTDti/d3TK+0FE4= X-Proofpoint-GUID: 2tyViaA4kN-1-mn6KuIjDs9B9ERzc_o4 X-Proofpoint-ORIG-GUID: 2tyViaA4kN-1-mn6KuIjDs9B9ERzc_o4 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 impostorscore=0 suspectscore=0 spamscore=0 priorityscore=1501 bulkscore=0 adultscore=0 lowpriorityscore=0 phishscore=0 clxscore=1015 malwarescore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2609040000 definitions=main-2609110214 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260911_082347_025609_3B11F568 X-CRM114-Status: GOOD ( 15.04 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org 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