From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> commit 99aed9227073fb34ce2880cbc7063e04185a65e1 upstream. It appears that firmware nodes can be shared between devices. In such case when a (child) device is about to be deleted, its firmware node may be shared and ACPI_COMPANION_SET(..., NULL) call for it breaks the secondary link of the shared primary firmware node. In order to prevent that, check, if the device has a parent and parent's firmware node is shared with its child, and avoid crashing the link. Fixes: c15e1bdda436 ("device property: Fix the secondary firmware node handling in set_primary_fwnode()") Reported-by: Ferry Toth <fntoth@xxxxxxxxx> Signed-off-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> Reviewed-by: Heikki Krogerus <heikki.krogerus@xxxxxxxxxxxxxxx> Tested-by: Ferry Toth <fntoth@xxxxxxxxx> Cc: 5.9+ <stable@xxxxxxxxxxxxxxx> # 5.9+ Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/base/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -3333,6 +3333,7 @@ static inline bool fwnode_is_primary(str */ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode) { + struct device *parent = dev->parent; struct fwnode_handle *fn = dev->fwnode; if (fwnode) { @@ -3347,7 +3348,8 @@ void set_primary_fwnode(struct device *d } else { if (fwnode_is_primary(fn)) { dev->fwnode = fn->secondary; - fn->secondary = ERR_PTR(-ENODEV); + if (!(parent && fn == parent->fwnode)) + fn->secondary = ERR_PTR(-ENODEV); } else { dev->fwnode = NULL; }