Medium [CVE-2026-72454] Fix race in i3c_hci_addr_to_dev

In the Linux kernel, the following vulnerability has been resolved: i3c: mipi-i3c-hci: Fix race in i3c_hci_addr_to_dev() i3c_hci_addr_to_dev() walks bus->devs.i3c, which is protected by bus.lock (rwsem). However, it is invoked from the MIPI I3C HCI IRQ handler, which cannot take bus.lock.

This allows concurrent device addition/removal in the I3C core to modify the list while it is being traversed, potentially leading to use-after-free or crashes. Remove the dependency on the bus device list and introduce a dedicated lookup table.

Add an ibi_devs[] array indexed by DAT entry, maintained under hci->lock. Update the array when IBIs are enabled or disabled, so that it always reflects the set of devices allowed to generate IBIs.

Also update when IBIs are freed, to cover the corner case when an IBI is freed without first being disabled (e.g. oldedev in i3c_master_add_i3c_dev_locked()). Move i3c_hci_addr_to_dev() into core.c, reimplement it using the new array, and add a lockdep assertion to enforce that hci->lock is held by callers.

Demote a message in PIO and DMA IBI handling, from an error to a debug message, because there is a race window when the condition can arise normally. A flaw was found in the Linux kernel's MIPI I3C Host Controller Interface (HCI) driver.

Affected products named by the advisory: Red Hat Enterprise Linux 10; Red Hat package: kernel.