[PATCH] staging: gpib: ines: Check the return value of ioremap()

[Haotian Zhang <vulab@iscas.ac.cn>]

The function ioremap() in ines_gpib_config() can fail and return NULL,
which is dereferenced without checking, leading to a NULL pointer
dereference.

Add a check for the return value of ioremap() and return -ENOMEM on
failure.

Fixes: bb1bd92fa0f2 ("staging: gpib: Add ines GPIB driver")
Signed-off-by: Haotian Zhang <vulab@iscas.ac.cn>
---
 drivers/staging/gpib/ines/ines_gpib.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/staging/gpib/ines/ines_gpib.c b/drivers/staging/gpib/ines/ines_gpib.c
index c851fd014f48..362a6310cab1 100644
--- a/drivers/staging/gpib/ines/ines_gpib.c
+++ b/drivers/staging/gpib/ines/ines_gpib.c
@@ -1144,6 +1144,11 @@ static int ines_gpib_config(struct pcmcia_device *link)
 		return -ENODEV;
 	}
 	virt = ioremap(link->resource[2]->start, resource_size(link->resource[2]));
+	if (!virt) {
+		dev_warn(&link->dev, "ioremap failed\n");
+		ines_gpib_release(link);
+		return -ENOMEM;
+	}
 	writeb((link->resource[2]->start >> 2) & 0xff, virt + 0xf0); // IOWindow base
 	iounmap(virt);
 
-- 
2.50.1.windows.1