CVE-2026-93202 i3c: master: Fix recursive locking during device registration
A recursive locking bug in the Linux kernel I3C master driver can cause a deadlock and system hang during device registration.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-93202?
CVE-2026-93202 is a vulnerability in Linux, published on 17 Sep 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-93202?
How do I fix CVE-2026-93202?
Apply the vendor's patch.
Is CVE-2026-93202 being exploited?
There is no known exploitation of CVE-2026-93202 in the wild and no public exploit code.
Sources
Also known as AZL-101906, BELL-CVE-2026-93202, DEBIAN-CVE-2026-93202, GHSA-w328-5f65-pqhc, UBUNTU-CVE-2026-93202.