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

Sasha Levin
2018-01-28T22:28:29Z

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@microsoft.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