CVE-2026-90192

In the Linux kernel, the following vulnerability has been resolved: mailbox: qcom-cpucp: handle NULL data in send_data callback 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.

• https://git.kernel.org/stable/c/3d11d2a6c9a10de287e0f1b53a5e65d16afe2760
• https://git.kernel.org/stable/c/413b0b94d6d06b8d49735280e86a01dac90cf177
• https://git.kernel.org/stable/c/b3d73e7440e0c40644285be1bda349cdf90122d8
• https://git.kernel.org/stable/c/fc4f2f99530298a1739226947aa76525142d421d