Commit 99aed922 authored Oct 22, 2020 by Andy Shevchenko Committed by Rafael J. Wysocki Oct 27, 2020

device property: Don't clear secondary pointer for shared primary firmware node

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: c15e1bdd ("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>

parent d5dcce0c

drivers/base/core.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -4264,6 +4264,7 @@ static inline bool fwnode_is_primary(struct fwnode_handle *fwnode)
		*/
		void set_primary_fwnode(struct device dev, struct fwnode_handle fwnode)
		{
		struct device *parent = dev->parent;
		struct fwnode_handle *fn = dev->fwnode;

		if (fwnode) {
		@@ -4278,6 +4279,7 @@ void set_primary_fwnode(struct device dev, struct fwnode_handle fwnode)
		} else {
		if (fwnode_is_primary(fn)) {
		dev->fwnode = fn->secondary;
		if (!(parent && fn == parent->fwnode))
		fn->secondary = ERR_PTR(-ENODEV);
		} else {
		dev->fwnode = NULL;

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