[PATCH v3] ALSA: ymfpci: Handle return NULL error from ioremap_nocache

[Arvind Yadav <arvind.yadav.cs@gmail.com>]

Here, If ioremap_nocache will fail. It will return NULL.
Kernel can run into a NULL-pointer dereference.
This error check will avoid NULL pointer dereference.

Signed-off-by: Arvind Yadav <arvind.yadav.cs@gmail.com>
---
 sound/pci/ymfpci/ymfpci_main.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/sound/pci/ymfpci/ymfpci_main.c b/sound/pci/ymfpci/ymfpci_main.c
index ffee284..8be1f07 100644
--- a/sound/pci/ymfpci/ymfpci_main.c
+++ b/sound/pci/ymfpci/ymfpci_main.c
@@ -2392,6 +2392,10 @@ int snd_ymfpci_create(struct snd_card *card,
 	chip->rev = pci->revision;
 	chip->reg_area_phys = pci_resource_start(pci, 0);
 	chip->reg_area_virt = ioremap_nocache(chip->reg_area_phys, 0x8000);
+	if (!chip->reg_area_virt) {
+		snd_ymfpci_free(chip);
+		return -ENOMEM;
+	}
 	pci_set_master(pci);
 	chip->src441_used = -1;
 
-- 
1.9.1