diff options
| author | Heikki Krogerus <heikki.krogerus@linux.intel.com> | 2021-06-23 16:14:21 +0300 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2021-06-23 19:34:58 +0200 |
| commit | 5dca69e26fe97f17d4a6cbd6872103c868577b14 (patch) | |
| tree | e6638b0f32b8b2ab911010141e923ab7349ef43c /drivers/base/swnode.c | |
| parent | 13311e74253fe64329390df80bed3f07314ddd61 (diff) | |
| download | lwn-5dca69e26fe97f17d4a6cbd6872103c868577b14.tar.gz lwn-5dca69e26fe97f17d4a6cbd6872103c868577b14.zip | |
software node: Handle software node injection to an existing device properly
The function software_node_notify() - the function that creates
and removes the symlinks between the node and the device - was
called unconditionally in device_add_software_node() and
device_remove_software_node(), but it needs to be called in
those functions only in the special case where the node is
added to a device that has already been registered.
This fixes NULL pointer dereference that happens if
device_remove_software_node() is used with device that was
never registered.
Fixes: b622b24519f5 ("software node: Allow node addition to already existing device")
Reported-and-tested-by: Dominik Brodowski <linux@dominikbrodowski.net>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/base/swnode.c')
| -rw-r--r-- | drivers/base/swnode.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/drivers/base/swnode.c b/drivers/base/swnode.c index 3cc11b813f28..d1f1a8240120 100644 --- a/drivers/base/swnode.c +++ b/drivers/base/swnode.c @@ -1045,7 +1045,15 @@ int device_add_software_node(struct device *dev, const struct software_node *nod } set_secondary_fwnode(dev, &swnode->fwnode); - software_node_notify(dev, KOBJ_ADD); + + /* + * If the device has been fully registered by the time this function is + * called, software_node_notify() must be called separately so that the + * symlinks get created and the reference count of the node is kept in + * balance. + */ + if (device_is_registered(dev)) + software_node_notify(dev, KOBJ_ADD); return 0; } @@ -1065,7 +1073,8 @@ void device_remove_software_node(struct device *dev) if (!swnode) return; - software_node_notify(dev, KOBJ_REMOVE); + if (device_is_registered(dev)) + software_node_notify(dev, KOBJ_REMOVE); set_secondary_fwnode(dev, NULL); kobject_put(&swnode->kobj); } @@ -1119,8 +1128,7 @@ int software_node_notify(struct device *dev, unsigned long action) switch (action) { case KOBJ_ADD: - ret = sysfs_create_link_nowarn(&dev->kobj, &swnode->kobj, - "software_node"); + ret = sysfs_create_link(&dev->kobj, &swnode->kobj, "software_node"); if (ret) break; |