1 files changed, 2 insertions, 1 deletions

diff --git a/arch/um/drivers/cow_user.c b/arch/um/drivers/cow_user.c
index a9afccf68e38..0ec4052db9c5 100644
--- a/arch/um/drivers/cow_user.c
+++ b/arch/um/drivers/cow_user.c
@@ -210,8 +210,9 @@ int write_cow_header(char *cow_file, int fd, char *backing_file,
 
         err = -EINVAL;
         if(strlen(backing_file) > sizeof(header->backing_file) - 1){
+                /* Below, %zd is for a size_t value */
                 cow_printf("Backing file name \"%s\" is too long - names are "
-                           "limited to %d characters\n", backing_file,
+                           "limited to %zd characters\n", backing_file,
                            sizeof(header->backing_file) - 1);
                 goto out_free;
         }