[PATCH AUTOSEL 4.4 43/56] video: hgafb: fix potential NULL pointer dereference

[Sasha Levin]

From: Kangjie Lu <kjlu at umn.edu>

[ Upstream commit ec7f6aad57ad29e4e66cc2e18e1e1599ddb02542 ]

When ioremap fails, hga_vram should not be dereferenced. The fix
check the failure to avoid NULL pointer dereference.

Signed-off-by: Kangjie Lu <kjlu at umn.edu>
Cc: Aditya Pakki <pakki001 at umn.edu>
Cc: Ferenc Bakonyi <fero at drama.obuda.kando.hu>
[b.zolnierkie: minor patch summary fixup]
Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie at samsung.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 drivers/video/fbdev/hgafb.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/video/fbdev/hgafb.c b/drivers/video/fbdev/hgafb.c
index 15d3ccff29654..4a397c7c1b560 100644
--- a/drivers/video/fbdev/hgafb.c
+++ b/drivers/video/fbdev/hgafb.c
@@ -285,6 +285,8 @@ static int hga_card_detect(void)
 	hga_vram_len  = 0x08000;
 
 	hga_vram = ioremap(0xb0000, hga_vram_len);
+	if (!hga_vram)
+		goto error;
 
 	if (request_region(0x3b0, 12, "hgafb"))
 		release_io_ports = 1;
-- 
2.20.1