In the Linux kernel, the following vulnerability has been resolved:
phy: qcom-qusb2: Fix NULL pointer dereference on early suspend
Enabling runtime PM before attaching the QPHY instance as driver data can lead to a NULL pointer dereference in runtime PM callbacks that expect valid driver data. There is a small window where the suspend callback may run after PM runtime enabling and before runtime forbid. This causes a sporadic crash during boot:
Unable to handle kernel NULL pointer dereference at virtual address 00000000000000a1
[...]
CPU: 0 UID: 0 PID: 11 Comm: kworker/0:1 Not tainted 6.16.7+ #116 PREEMPT
Workqueue: pm pm_runtime_work
pstate: 20000005 (nzCv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : qusb2_phy_runtime_suspend+0x14/0x1e0 [phy_qcom_qusb2]
lr : pm_generic_runtime_suspend+0x2c/0x44
[...]
Attach the QPHY instance as driver data before enabling runtime PM to prevent NULL pointer dereference in runtime PM callbacks.
Reorder pm_runtime_enable() and pm_runtime_forbid() to prevent a short window where an unnecessary runtime suspend can occur.
Use the devres-managed version to ensure PM runtime is symmetrically disabled during driver removal for proper cleanup.