linux-kernel - [PATCH AUTOSEL for 4.14 098/100] PCI: rcar: Fix use-after-free in probe error path

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Message-ID: <20180128222547.7398-98-alexander.levin@microsoft.com>
Date:   Sun, 28 Jan 2018 22:27:04 +0000
From:   Sasha Levin <Alexander.Levin@...rosoft.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "stable@...r.kernel.org" <stable@...r.kernel.org>
CC:     Geert Uytterhoeven <geert+renesas@...der.be>,
        Bjorn Helgaas <bhelgaas@...gle.com>,
        Sasha Levin <Alexander.Levin@...rosoft.com>
Subject: [PATCH AUTOSEL for 4.14 098/100] PCI: rcar: Fix use-after-free in
 probe error path

From: Geert Uytterhoeven <geert+renesas@...der.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@...der.be>
Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
Acked-by: Simon Horman <horms+renesas@...ge.net.au>
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@....com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
---
 drivers/pci/host/pcie-rcar.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/pci/host/pcie-rcar.c b/drivers/pci/host/pcie-rcar.c
index 4e0b25d09b0c..f09ff4789bb5 100644
--- a/drivers/pci/host/pcie-rcar.c
+++ b/drivers/pci/host/pcie-rcar.c
@@ -1146,12 +1146,12 @@ static int rcar_pcie_probe(struct platform_device *pdev)
 	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 @@ static int rcar_pcie_probe(struct platform_device *pdev)
 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;
 }
-- 
2.11.0