From: Andy Shevchenko andriy.shevchenko@linux.intel.com
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@gmail.com Signed-off-by: Andy Shevchenko andriy.shevchenko@linux.intel.com Reviewed-by: Heikki Krogerus heikki.krogerus@linux.intel.com Tested-by: Ferry Toth fntoth@gmail.com Cc: 5.9+ stable@vger.kernel.org # 5.9+ Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/base/core.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
--- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -4260,6 +4260,7 @@ 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) { @@ -4274,7 +4275,8 @@ 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; }