[PATCH 6.1 157/291] PCI: Fix reference leak in pci_alloc_child_bus()

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Ma Ke <redacted>

commit 1f2768b6a3ee77a295106e3a5d68458064923ede upstream.

If device_register(&child->dev) fails, call put_device() to explicitly
release child->dev, per the comment at device_register().

Found by code review.

Link: https://lore.kernel.org/r/20250202062357.872971-1-make24@iscas.ac.cn (local)
Fixes: 4f535093cf8f ("PCI: Put pci_dev in device tree as early as possible")
Signed-off-by: Ma Ke <redacted>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/pci/probe.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c

@@ -1141,7 +1141,10 @@ static struct pci_bus *pci_alloc_child_b
 add_dev:
 	pci_set_bus_msi_domain(child);
 	ret = device_register(&child->dev);
-	WARN_ON(ret < 0);
+	if (WARN_ON(ret < 0)) {
+		put_device(&child->dev);
+		return NULL;
+	}
 
 	pcibios_add_bus(child);