1 files changed, 4 insertions, 0 deletions

diff --git a/arch/s390/lib/uaccess_pt.c b/arch/s390/lib/uaccess_pt.c
index a70ee84c0241..c1aaf22c326b 100644
--- a/arch/s390/lib/uaccess_pt.c
+++ b/arch/s390/lib/uaccess_pt.c
@@ -172,6 +172,8 @@ static size_t strnlen_user_pt(size_t count, const char __user *src)
         unsigned long offset, done, len, kaddr;
         size_t len_str;
 
+        if (unlikely(!count))
+                return 0;
         if (segment_eq(get_fs(), KERNEL_DS))
                 return strnlen((const char __kernel __force *) src, count) + 1;
         done = 0;
@@ -202,6 +204,8 @@ static size_t strncpy_from_user_pt(size_t count, const char __user *src,
 {
         size_t n = strnlen_user_pt(count, src);
 
+        if (unlikely(!count))
+                return 0;
         if (!n)
                 return -EFAULT;
         if (n > count)