[v16, 6/7] base: soc: Check for NULL SoC device attributes

[Yangbo Lu]

From: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

If soc_device_match() is used to check the value of a specific
attribute that is not present for the current SoC, the kernel crashes
with a NULL pointer dereference.

Fix this by explicitly checking for the absence of a needed property,
and considering this a non-match.

Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
Acked-by: Arnd Bergmann <arnd@xxxxxxxx>
---
Changes for v16:
	- Added this patch
---
 drivers/base/soc.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/base/soc.c b/drivers/base/soc.c
index 0c5cf87..0e701e2 100644
--- a/drivers/base/soc.c
+++ b/drivers/base/soc.c
@@ -167,19 +167,23 @@ static int soc_device_match_one(struct device *dev, void *arg)
 	const struct soc_device_attribute *match = arg;
 
 	if (match->machine &&
-	    !glob_match(match->machine, soc_dev->attr->machine))
+	    (!soc_dev->attr->machine ||
+	     !glob_match(match->machine, soc_dev->attr->machine)))
 		return 0;
 
 	if (match->family &&
-	    !glob_match(match->family, soc_dev->attr->family))
+	    (!soc_dev->attr->family ||
+	     !glob_match(match->family, soc_dev->attr->family)))
 		return 0;
 
 	if (match->revision &&
-	    !glob_match(match->revision, soc_dev->attr->revision))
+	    (!soc_dev->attr->revision ||
+	     !glob_match(match->revision, soc_dev->attr->revision)))
 		return 0;
 
 	if (match->soc_id &&
-	    !glob_match(match->soc_id, soc_dev->attr->soc_id))
+	    (!soc_dev->attr->soc_id ||
+	     !glob_match(match->soc_id, soc_dev->attr->soc_id)))
 		return 0;
 
 	return 1;
-- 
2.1.0.27.g96db324