[PATCH 4.9 044/117] PCI: rcar: Fix a potential NULL pointer dereference

[Greg Kroah-Hartman]

[ Upstream commit f0d14edd2ba43b995bef4dd5da5ffe0ae19321a1 ]

In case __get_free_pages() fails and returns NULL, fix the return
value to -ENOMEM and release resources to avoid dereferencing a
NULL pointer.

Signed-off-by: Kangjie Lu <kjlu@xxxxxxx>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@xxxxxxx>
Reviewed-by: Ulrich Hecht <uli+renesas@xxxxxxxx>
Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Reviewed-by: Simon Horman <horms+renesas@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/pci/host/pcie-rcar.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/pci/host/pcie-rcar.c b/drivers/pci/host/pcie-rcar.c
index d6196f7b1d58..77d931178178 100644
--- a/drivers/pci/host/pcie-rcar.c
+++ b/drivers/pci/host/pcie-rcar.c
@@ -886,6 +886,10 @@ static int rcar_pcie_enable_msi(struct rcar_pcie *pcie)
 
 	/* setup MSI data target */
 	msi->pages = __get_free_pages(GFP_KERNEL, 0);
+	if (!msi->pages) {
+		err = -ENOMEM;
+		goto err;
+	}
 	base = virt_to_phys((void *)msi->pages);
 
 	rcar_pci_write_reg(pcie, base | MSIFE, PCIEMSIALR);
-- 
2.20.1