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charset=UTF-8 Content-Transfer-Encoding: 7bit X-Authority-Analysis: v=2.4 cv=Ua9hjqSN c=1 sm=1 tr=0 ts=6a82f149 cx=c_pps a=oc9J++0uMp73DTRD5QyR2A==:117 a=PRfkaYvzSr8QmIIGAkY2Sg==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=s4-Qcg_JpJYA:10 a=VkNPw1HP01LnGYTKEx00:22 a=u7WPNUs3qKkmUXheDGA7:22 a=_K5XuSEh1TEqbUxoQ0s3:22 a=EUspDBNiAAAA:8 a=FIVuYjU95cRvfn1gDQ0A:9 a=QEXdDO2ut3YA:10 a=iYH6xdkBrDN1Jqds4HTS:22 X-Proofpoint-GUID: o2oIQfZ3DNNj7Gv5fF-YQyv3WW9pfySP X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODE3MDA4NyBTYWx0ZWRfX5ccF+km10FwA w2J6lFKIUs1qfGEA/XI2SXoGcp9FzlUDyJG20s4ptFJ1t3t912ok6Z8b+c60o0KUxqAkvxtcHmN xu4v7K6l0bBajdatSoP8im43R375XufJwCHw1niqM+kHIdo0FyP5S+6wilWBJgUu8dhji8ZkbUw YJYVAuUnwBMcHSHaTD5XUh/ehhCMY8W/O8rtkUjGlq6JDNCNldkGEBlAwX9f09H3LluCJXnP+BS 5hS8f4nhoFh1lflIKqUoQYCVJOUD9dUJ+XuBtUW7kOnH1vQsMO1bNcuu79vT+1bcpYzPbjwi266 aRsz40xrew5L62ivy6/P2kdfKYKYik81dXTpciPwjer6yAqFXZVmLkErsrrxiY59ccX/wXkykbX FSJEi+5EOHMl3EtVXBsfqc0iZ/3jYED+YDVvT/b4+hidW7H5ZPi+5TU34ltqXd+haPgj6sykZEt PoW1h1W8WOtiuv/oKzQ== X-Proofpoint-Spam-Info: AW1haW4tMjYwODE3MDA4NyBTYWx0ZWRfXwvqD8aE3EcYK 3LoIt4Bz8FB5Mr1TI+uk7H8WRjirEhqdl5ox+fMSQujapdtA+fLunZJqg76U1rQlhIi1LxHhfVl dZrF8atbLNAR4N0stHX/gmw+JGaEheI= X-Proofpoint-ORIG-GUID: o2oIQfZ3DNNj7Gv5fF-YQyv3WW9pfySP 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=2026-08-16_06,2026-08-12_01,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 adultscore=0 priorityscore=1501 malwarescore=0 suspectscore=0 impostorscore=0 bulkscore=0 lowpriorityscore=0 phishscore=0 clxscore=1015 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608170087 On 8/6/26 9:03 AM, Jia Yang wrote: > mailbox_clear_channel() calls mbox_send_message() with NULL data to > notify the remote side that the RX channel has been cleared. > qcom_cpucp_mbox_send_data() blindly dereferenced the data pointer, > causing a NULL pointer dereference kernel panic when invoked from > this path under PREEMPT_RT. > > Add an explicit NULL check and return early without writing to the > TX register, which is the correct behaviour for a channel-clear > notification. > > Fixes: 0e2a9a03106c ("mailbox: Add support for QTI CPUCP mailbox controller") > Signed-off-by: Jia Yang > --- > drivers/mailbox/qcom-cpucp-mbox.c | 8 ++++++++ > 1 file changed, 8 insertions(+) > > diff --git a/drivers/mailbox/qcom-cpucp-mbox.c b/drivers/mailbox/qcom-cpucp-mbox.c > index 0f7fe189e8b1..298b357c0f9a 100644 > --- a/drivers/mailbox/qcom-cpucp-mbox.c > +++ b/drivers/mailbox/qcom-cpucp-mbox.c > @@ -117,6 +117,14 @@ static int qcom_cpucp_mbox_send_data(struct mbox_chan *chan, void *data) > unsigned long chan_id = channel_number(chan); > u32 *val = data; > > + /* > + * mailbox_clear_channel() calls mbox_send_message() with NULL data to > + * signal the remote side that the channel has been cleared. Nothing > + * needs to be written to the TX register in that case, so just return. > + */ > + if (!val) > + return 0; Is this a bug in the scmi driver itself? Is a message with val=0 valid as far as our mailbox is concerned? Konrad