cxl: fix potential NULL dereference in free_adapter()

If kzalloc() fails when allocating adapter->guest in cxl_guest_init_adapter(), we call free_adapter() before erroring out. free_adapter() in turn attempts to dereference adapter->guest, which in this case is NULL. In free_adapter(), skip the adapter->guest cleanup if adapter->guest is NULL. Fixes: 14baf4d ("cxl: Add guest-specific code") Reported-by: Dan Carpenter <[email protected]> Signed-off-by: Andrew Donnellan <[email protected]> Signed-off-by: Michael Ellerman <[email protected]>
chewitt · Jul 19, 2016 · 8fbaa51 · 8fbaa51
1 parent 1e44727
commit 8fbaa51
Showing 1 changed file with 9 additions and 7 deletions.
diff --git a/drivers/misc/cxl/guest.c b/drivers/misc/cxl/guest.c
@@ -1055,16 +1055,18 @@ static void free_adapter(struct cxl *adapter)
 	struct irq_avail *cur;
 	int i;
 
-	if (adapter->guest->irq_avail) {
-		for (i = 0; i < adapter->guest->irq_nranges; i++) {
-			cur = &adapter->guest->irq_avail[i];
-			kfree(cur->bitmap);
+	if (adapter->guest) {
+		if (adapter->guest->irq_avail) {
+			for (i = 0; i < adapter->guest->irq_nranges; i++) {
+				cur = &adapter->guest->irq_avail[i];
+				kfree(cur->bitmap);
+			}
+			kfree(adapter->guest->irq_avail);
 		}
-		kfree(adapter->guest->irq_avail);
+		kfree(adapter->guest->status);
+		kfree(adapter->guest);
 	}
-	kfree(adapter->guest->status);
 	cxl_remove_adapter_nr(adapter);
-	kfree(adapter->guest);
 	kfree(adapter);
 }