FAILED: patch "[PATCH] PCI: Allow release of resources that were never assigned" failed to apply to 4.15-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.15-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From c37406e05d1e541df40b8b81c4bd40753fcaf414 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <ckoenig.leichtzumerken@gmail.com>
Date: Mon, 26 Feb 2018 14:51:13 -0600
Subject: [PATCH] PCI: Allow release of resources that were never assigned
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It is entirely possible that the BIOS wasn't able to assign resources to a
device. In this case don't crash in pci_release_resource() when we try to
resize the resource.

Fixes: 8bb705e3e79d ("PCI: Add pci_resize_resource() for resizing BARs")
Signed-off-by: Christian König <christian.koenig@amd.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
CC: stable@vger.kernel.org	# v4.15+

diff --git a/drivers/pci/setup-res.c b/drivers/pci/setup-res.c
index 369d48d6c6f1..365447240d95 100644
--- a/drivers/pci/setup-res.c
+++ b/drivers/pci/setup-res.c
@@ -401,6 +401,10 @@ void pci_release_resource(struct pci_dev *dev, int resno)
 	struct resource *res = dev->resource + resno;
 
 	pci_info(dev, "BAR %d: releasing %pR\n", resno, res);
+
+	if (!res->parent)
+		return;
+
 	release_resource(res);
 	res->end = resource_size(res) - 1;
 	res->start = 0;