--- zzzz-none-000/linux-3.10.107/arch/alpha/lib/csum_partial_copy.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/alpha/lib/csum_partial_copy.c	2021-02-04 17:41:59.000000000 +0000
@@ -130,7 +130,7 @@
 		*dst = word | tmp;
 		checksum += carry;
 	}
-	if (err) *errp = err;
+	if (err && errp) *errp = err;
 	return checksum;
 }
 
@@ -185,7 +185,7 @@
 		*dst = word | tmp;
 		checksum += carry;
 	}
-	if (err) *errp = err;
+	if (err && errp) *errp = err;
 	return checksum;
 }
 
@@ -242,7 +242,7 @@
 	stq_u(partial_dest | second_dest, dst);
 out:
 	checksum += carry;
-	if (err) *errp = err;
+	if (err && errp) *errp = err;
 	return checksum;
 }
 
@@ -325,7 +325,7 @@
 		stq_u(partial_dest | word | second_dest, dst);
 		checksum += carry;
 	}
-	if (err) *errp = err;
+	if (err && errp) *errp = err;
 	return checksum;
 }
 
@@ -338,6 +338,11 @@
 	unsigned long doff = 7 & (unsigned long) dst;
 
 	if (len) {
+		if (!access_ok(VERIFY_READ, src, len)) {
+			if (errp) *errp = -EFAULT;
+			memset(dst, 0, len);
+			return sum;
+		}
 		if (!doff) {
 			if (!soff)
 				checksum = csum_partial_cfu_aligned(
@@ -373,6 +378,11 @@
 __wsum
 csum_partial_copy_nocheck(const void *src, void *dst, int len, __wsum sum)
 {
-	return csum_partial_copy_from_user((__force const void __user *)src,
-			dst, len, sum, NULL);
+	__wsum checksum;
+	mm_segment_t oldfs = get_fs();
+	set_fs(KERNEL_DS);
+	checksum = csum_partial_copy_from_user((__force const void __user *)src,
+						dst, len, sum, NULL);
+	set_fs(oldfs);
+	return checksum;
 }