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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: c15e1bdda4 ("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>
zero-sugar-mainline-defconfig
Andy Shevchenko 2020-10-22 21:41:00 +03:00 committed by Rafael J. Wysocki
parent d5dcce0c41
commit 99aed92270
1 changed files with 3 additions and 1 deletions
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4
drivers/base/core.c
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@ -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) {
@ -4278,7 +4279,8 @@ void set_primary_fwnode(struct device *dev, struct fwnode_handle *fwnode)
} 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;
}