published September 17, 2026
In the Linux kernel, the following vulnerability has been resolved:
i3c: master: Fix recursive locking during device registration
i3c_master_register_new_i3c_devs() registers newly discovered devices
while holding i3c_bus_normaluse_lock(), a down_read(). device_register()
can immediately probe the device, and probe callbacks typically invoke
I3C helpers that take i3c_bus_normaluse_lock() again, leading to a
recursive acquisition of the same rwsem. rwsems do not support recursive
read locking and can deadlock when a writer is waiting. See the
"Recursive read locks" section of Documentation/locking/lockdep-design.rst.
For example, with Intel LPSS I3C, LOCKDEP generates a WARNING like:
# echo intel-lpss-i3c.0 > /sys/bus/platform/drivers/mipi-i3c-hci/unbind
# echo intel-lpss-i3c.0 > /sys/bus/platform/drivers/mipi-i3c-hci/bind
WARNING: possible recursive locking detected
kworker/5:1/94 is trying to acquire lock:
ffff88811c810d78 (&i3cbus->lock){++++}-{4:4}, at: i3c_device_match_id+0x45/0x370
but task is already holding lock:
ffff88811c810d78 (&i3cbus->lock){++++}-{4:4}, at: i3c_master_reg_work_fn+0x21/0x5f0
Fix this by separating device creation from device registration.
Populate desc->dev under the maintenance lock, collect the devices that
still need registration into a local list, then release the lock before
calling device_register(). Finally retake the lock and clean up any
devices that failed to register.
Use the maintenance lock rather than the normal-use lock while adding
device objects. A write-side maintenance lock prevents readers from
observing a partially initialized desc->dev during initial device
population, or desc->dev disappearing if registration fails.
The local list requires a list node, so add a list node member to struct
i3c_device.