lib/string.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/lib/string.c b/lib/string.c
index 76327b51e36f..a2a678e45389 100644
--- a/lib/string.c
+++ b/lib/string.c
@@ -137,7 +137,7 @@ ssize_t sized_strscpy(char *dest, const char *src, size_t count)
 	if (IS_ENABLED(CONFIG_KMSAN))
 		max = 0;
 
-	while (max >= sizeof(unsigned long)) {
+	while (max > sizeof(unsigned long)) {
 		unsigned long c, data;
 
 		c = read_word_at_a_time(src+res);
@@ -153,10 +153,10 @@ ssize_t sized_strscpy(char *dest, const char *src, size_t count)
 		max -= sizeof(unsigned long);
 	}
 
-	while (count) {
+	while (count > 0) {
 		char c;
 
-		c = src[res];
+		c = READ_ONCE(src[res]);
 		dest[res] = c;
 		if (!c)
 			return res;
@@ -164,11 +164,11 @@ ssize_t sized_strscpy(char *dest, const char *src, size_t count)
 		count--;
 	}
 
-	/* Hit buffer length without finding a NUL; force NUL-termination. */
-	if (res)
-		dest[res-1] = '\0';
+	/* Final byte - force NUL termination */
+	dest[res] = 0;
 
-	return -E2BIG;
+	/* Return -E2BIG if the source continued.. */
+	return READ_ONCE(src[res]) ? -E2BIG : res;
 }
 EXPORT_SYMBOL(sized_strscpy);