[PATCH] iommu: apple-dart: fix potential null pointer deref

[Qasim Ijaz]

If kzalloc() fails, accessing cfg->supports_bypass causes a null pointer dereference. 

Fix by checking for NULL immediately after allocation and returning -ENOMEM.

Fixes: 3bc0102835f6 ("iommu: apple-dart: Allow mismatched bypass support")
Signed-off-by: Qasim Ijaz <qasdev00 at gmail.com>
---
 drivers/iommu/apple-dart.c | 5 ++---
 1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/drivers/iommu/apple-dart.c b/drivers/iommu/apple-dart.c
index 13ccb801f52a..e13501541fdd 100644
--- a/drivers/iommu/apple-dart.c
+++ b/drivers/iommu/apple-dart.c
@@ -797,12 +797,11 @@ static int apple_dart_of_xlate(struct device *dev,
 
 	if (!cfg) {
 		cfg = kzalloc(sizeof(*cfg), GFP_KERNEL);
-
+		if (!cfg)
+			return -ENOMEM;
 		/* Will be ANDed with DART capabilities */
 		cfg->supports_bypass = true;
 	}
-	if (!cfg)
-		return -ENOMEM;
 	dev_iommu_priv_set(dev, cfg);
 
 	cfg_dart = cfg->stream_maps[0].dart;
-- 
2.39.5