[PATCH 4.4 28/84] PCI: rcar: Fix a potential NULL pointer dereference

From: Greg Kroah-Hartman
Date: Thu Jun 20 2019 - 13:59:21 EST


[ 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 414c33686621..b18cf12731ee 100644
--- a/drivers/pci/host/pcie-rcar.c
+++ b/drivers/pci/host/pcie-rcar.c
@@ -737,6 +737,10 @@ 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