PCI: rcar: Fix a potential NULL pointer dereference

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@umn.edu>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Reviewed-by: Ulrich Hecht <uli+renesas@fpond.eu>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/pci/controller/pcie-rcar.c b/drivers/pci/controller/pcie-rcar.c
index a25527185bf1..0004b6457124 100644
--- a/drivers/pci/controller/pcie-rcar.c
+++ b/drivers/pci/controller/pcie-rcar.c
@@ -929,6 +929,10 @@ 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, lower_32_bits(base) | MSIFE, PCIEMSIALR);