kernel/git/stable/linux.git/drivers/i3c/master.c, branch linux-7.2.y

i3c: master: Do not treat master device as a duplicate target

2026-09-14T11:39:00+00:00

[ Upstream commit 4dc1b3eeba7991905a5b5b8129ebea51be7d87b7 ] i3c_master_search_i3c_dev_duplicate() searches the bus for another I3C device with the same PID as the reference device. The search can match master->this, causing the controller itself to be returned as a duplicate. Since the controller is not a target device, it cannot be a duplicate of one. Exclude master->this from matching so that the function only returns real duplicate target devices. Fixes: 3a379bbcea0a ("i3c: Add core I3C infrastructure") Cc: stable@vger.kernel.org Signed-off-by: Adrian Hunter Reviewed-by: Frank Li Acked-by: Mukesh Savaliya Link: https://patch.msgid.link/20260807145638.168865-4-adrian.hunter@intel.com Signed-off-by: Alexandre Belloni [ adjusted the duplicate-device comparison to match the older branch’s PID handling without nonzero-PID checks. ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

i3c: master: Fix use-after-free of master->this

2026-09-14T11:39:00+00:00

[ Upstream commit feb0ed76601f3c2f91f08688c5a7d8b9d382f720 ] sysfs attribute callbacks for the master controller device dereference master->this. However, master->this is freed in i3c_master_detach_free_devs() before the master device itself is released. As a result, sysfs accesses can dereference a freed master->this pointer, leading to a use-after-free. Keep master->this alive until i3c_masterdev_release(), which is called after the master device and its sysfs state are being torn down. Do not free master->this as part of the normal device detach path. On the error path in i3c_master_set_info(), reset master->this and bus.cur_master to NULL before freeing the allocated device. Fixes: 3a379bbcea0a ("i3c: Add core I3C infrastructure") Cc: stable@vger.kernel.org Signed-off-by: Adrian Hunter Reviewed-by: Frank Li Link: https://patch.msgid.link/20260807145638.168865-5-adrian.hunter@intel.com Signed-off-by: Alexandre Belloni [ retained of_node_put(dev->of_node) instead of upstream’s fwnode_handle_put(dev->fwnode). ] Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

i3c: master: Fix recursive locking during device registration

2026-09-14T11:39:00+00:00

[ Upstream commit 456f832e5fc26fbfd3b8200fd4553eee520cc377 ] 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. Fixes: 3a379bbcea0a ("i3c: Add core I3C infrastructure") Cc: stable@vger.kernel.org Signed-off-by: Adrian Hunter Reviewed-by: Frank Li Link: https://patch.msgid.link/20260807145638.168865-2-adrian.hunter@intel.com Signed-off-by: Alexandre Belloni Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

i3c: master: Fix device_register() error path

2026-09-14T11:39:00+00:00

[ Upstream commit 74be657d98a8d684c0475f3cbd450ef2a30ffc73 ] When device_register() fails in i3c_master_register_new_i3c_devs(), put_device() is called to drop the reference taken by device_register(). That drops the last reference, so the device's release callback i3c_device_release() runs and frees the i3c_device. Two problems follow from that: i3c_device_release() does WARN_ON(i3cdev->desc), so it warns because desc->dev->desc still points back at the descriptor. Clear it before calling put_device(). After put_device() frees the i3c_device, desc->dev is left pointing at freed memory, so clear desc->dev as well. That prevents, for example, i3c_master_unregister_i3c_devs() seeing desc->dev as non-NULL and dereferencing it. Reported-by: sashiko-bot@kernel.org Link: https://lore.kernel.org/linux-i3c/20260701203053.8F3971F000E9@smtp.kernel.org/ Fixes: cab63f6488761 ("i3c: Fix potential refcount leak in i3c_master_register_new_i3c_devs") Signed-off-by: Adrian Hunter Reviewed-by: Frank Li Link: https://patch.msgid.link/20260702183644.60827-1-adrian.hunter@intel.com Signed-off-by: Alexandre Belloni Stable-dep-of: 456f832e5fc2 ("i3c: master: Fix recursive locking during device registration") Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

i3c: master: Fix info leak and UAF in device unregister path

2026-09-07T15:37:24+00:00

commit d2c743efd2d1ee64e94324664808f623dd865872 upstream. i3c_master_unregister_i3c_devs() clears i3cdev->dev->desc before calling device_unregister(). During device_unregister(), device_del() emits a KOBJ_REMOVE uevent and unbinds the driver while the device descriptor is still expected to be valid. As a result, i3c_device_uevent() and a racing modalias_show() can observe a NULL desc and fall back to an uninitialized stack struct i3c_device_info, leaking kernel stack contents in the generated modalias. Driver .remove() callbacks may also encounter an unexpected NULL desc during unbind. Keep desc valid until device_unregister() has completed. Since device_unregister() drops the device reference and may free the device, take an extra reference with get_device() before unregistering. Clear desc afterwards and release the extra reference with put_device(). This preserves the release-time invariant that desc must be NULL while avoiding both the information leak and a potential use-after-free from writing desc after the device has been released. Reported-by: sashiko-bot@kernel.org Link: https://lore.kernel.org/linux-i3c/20260702190003.8BF741F000E9@smtp.kernel.org/ Fixes: 3a379bbcea0a ("i3c: Add core I3C infrastructure") Cc: stable@vger.kernel.org Signed-off-by: Adrian Hunter Reviewed-by: Frank Li Link: https://patch.msgid.link/20260723075747.34049-1-adrian.hunter@intel.com Signed-off-by: Alexandre Belloni Signed-off-by: Greg Kroah-Hartman

i3c: Fix unlocked dereference of dev->desc in i3c_device_get_supported_xfer_mode()

2026-09-07T15:37:24+00:00

commit 8bed7f4fa710914b7f05fd59998316bfb4d43385 upstream. i3c_device_get_supported_xfer_mode() uses dev->desc to obtain the master controller. However, dev->desc must not be dereferenced unless bus->lock is held, and this function does not take that lock. The function only needs access to the master controller associated with the device's bus. Use dev->bus instead, which is always valid for the lifetime of the device and does not require dereferencing dev->desc. Fixes: 256a21743d91 ("i3c: Add HDR API support") Cc: stable@vger.kernel.org Signed-off-by: Adrian Hunter Reviewed-by: Frank Li Link: https://patch.msgid.link/20260807145638.168865-3-adrian.hunter@intel.com Signed-off-by: Alexandre Belloni Signed-off-by: Greg Kroah-Hartman

i3c: master: Use unsigned int for dev_nack_retry_count consistently

2026-06-16T21:19:19+00:00

Use unsigned int for dev_nack_retry_count across the core and controller drivers to match the type of master->dev_nack_retry_count. Update the sysfs store path to use kstrtouint() and adjust the ->set_dev_nack_retry() callback prototype and callers accordingly. Signed-off-by: Adrian Hunter Reviewed-by: Frank Li Link: https://patch.msgid.link/20260616113752.196140-4-adrian.hunter@intel.com Signed-off-by: Alexandre Belloni

i3c: master: Add missing runtime PM get in dev_nack_retry_count_store()

2026-06-16T21:19:19+00:00

Ensure the device is runtime resumed while updating the retry configuration to avoid accessing the controller while suspended. Call i3c_master_rpm_get() before accessing the controller in dev_nack_retry_count_store() and release it with i3c_master_rpm_put() afterwards. Fixes: 990c149c61ee4 ("i3c: master: Introduce optional Runtime PM support") Signed-off-by: Adrian Hunter Reviewed-by: Frank Li Link: https://patch.msgid.link/20260616113752.196140-3-adrian.hunter@intel.com Signed-off-by: Alexandre Belloni

i3c: master: Update dev_nack_retry_count under maintenance lock

2026-06-16T21:19:19+00:00

Protect master->dev_nack_retry_count against concurrent sysfs updates by updating it while holding the bus maintenance lock. Consequently, combine adjacent return statements into one. For consistency, read dev_nack_retry_count while holding the bus normaluse lock. Fixes: b58f47eb39268 ("i3c: add sysfs entry and attribute for Device NACK Retry count") Signed-off-by: Adrian Hunter Reviewed-by: Frank Li Link: https://patch.msgid.link/20260616113752.196140-2-adrian.hunter@intel.com Signed-off-by: Alexandre Belloni

i3c: master: Expose the APIs to support I3C hub

2026-06-15T23:27:25+00:00

Change the below internal static functions to APIs to allow new I3C hub driver to use them 1) i3c_dev_enable_ibi_locked() 2) i3c_dev_disable_ibi_locked() 3) i3c_dev_request_ibi_locked() 4) i3c_dev_free_ibi_locked() 5) i3c_master_reattach_i3c_dev_locked() Signed-off-by: Aman Kumar Pandey Signed-off-by: Lakshay Piplani Reviewed-by: Frank Li Link: https://patch.msgid.link/20260612111816.3688240-3-lakshay.piplani@nxp.com Signed-off-by: Alexandre Belloni