[PATCH v2 0/3] driver core: fix unbalanced reference counting for software nodes

[Bartosz Golaszewski]

Eduardo reported an issue with reference underflow when setting a
software node with set_secondary_fwnode() and then repeatedly destroying
and re-creating a device. This is caused by the fact that
software_node_notify() takes a reference to the software node which is
unconditionally dropped in software_node_notify_remove(). However the
software node can be assigned after device_add() so the latter should
only do it if it was bumped by the former.

This series proposes a fix in driver core. The first two patches extend
the device flag API with a new accessor and value. The third is the
actual fix in swnode.c and should be backported to stable (along the
first two as dependencies).

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
---
Changes in v2:
- Fix typo in kerneldoc for the new flag
- Link to v1: https://patch.msgid.link/20261015-swnode-dev-notify-balance-v1-0-9e7537bd2869@xxxxxxxxxxxxxxxx

---
Bartosz Golaszewski (3):
      driver core: provide a test-and-clear device flag accessor
      driver core: provide new device flag - DEV_FLAG_SWNODE_NOTIFIER
      software node: fix unbalanced reference counting

 drivers/base/swnode.c  |  5 ++++-
 include/linux/device.h | 10 ++++++++++
 2 files changed, 14 insertions(+), 1 deletion(-)
---
base-commit: bd1ecbb61afefc6a8b876ccbc31e9228b44e9eab
change-id: 20261015-swnode-dev-notify-balance-e6f56fb9a469

Best regards,
-- 
Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxxxxxxxx>