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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Geert Uytterhoeven <geert+renesas@glider.be>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Simon Horman <horms+renesas@verge.net.au>,
        Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
        Sasha Levin <alexander.levin@verizon.com>
Subject: [PATCH 4.14 151/159] PCI: rcar: Fix use-after-free in probe error path
Date:   Fri, 23 Feb 2018 19:27:39 +0100
Message-Id: <20180223170801.222910037@linuxfoundation.org>
In-Reply-To: <20180223170743.086611315@linuxfoundation.org>
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4.14-stable review patch.  If anyone has any objections, please let me know.

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

From: Geert Uytterhoeven <geert+renesas@glider.be>


[ Upstream commit 0c31f1d7be1b5c4858b1d714dcefa25f41428cab ]

If CONFIG_DEBUG_SLAB=y, and no PCIe card is inserted, the kernel crashes
during probe on r8a7791/koelsch:

  rcar-pcie fe000000.pcie: PCIe link down
  Unable to handle kernel paging request at virtual address 6b6b6b6b

(seeing this message requires earlycon and keep_bootcon).

Indeed, pci_free_host_bridge() frees the PCI host bridge, including the
embedded rcar_pcie object, so pci_free_resource_list() must not be called
afterwards.

To fix this, move the call to pci_free_resource_list() up, and update the
label name accordingly.

Fixes: ddd535f1ea3eb27e ("PCI: rcar: Fix memory leak when no PCIe card is inserted")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/pci/host/pcie-rcar.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/drivers/pci/host/pcie-rcar.c
+++ b/drivers/pci/host/pcie-rcar.c
@@ -1146,12 +1146,12 @@ static int rcar_pcie_probe(struct platfo
 	err = rcar_pcie_get_resources(pcie);
 	if (err < 0) {
 		dev_err(dev, "failed to request resources: %d\n", err);
-		goto err_free_bridge;
+		goto err_free_resource_list;
 	}
 
 	err = rcar_pcie_parse_map_dma_ranges(pcie, dev->of_node);
 	if (err)
-		goto err_free_bridge;
+		goto err_free_resource_list;
 
 	pm_runtime_enable(dev);
 	err = pm_runtime_get_sync(dev);
@@ -1194,9 +1194,9 @@ err_pm_put:
 err_pm_disable:
 	pm_runtime_disable(dev);
 
-err_free_bridge:
-	pci_free_host_bridge(bridge);
+err_free_resource_list:
 	pci_free_resource_list(&pcie->resources);
+	pci_free_host_bridge(bridge);
 
 	return err;
 }