Author: Florian Weimer <fweimer@redhat.com>
Date:   Wed Nov 15 06:31:40 2023 +0100

    stdlib: Avoid another self-comparison in qsort
    
    In the insertion phase, we could run off the start of the array if the
    comparison function never runs zero.  In that case, it never finds the
    initial element that terminates the iteration.

diff --git a/stdlib/qsort.c b/stdlib/qsort.c
index ad110e8a892a66e1..1ea31ff4247da7a4 100644
--- a/stdlib/qsort.c
+++ b/stdlib/qsort.c
@@ -217,7 +217,7 @@ insertion_sort_qsort_partitions (void *const pbase, size_t total_elems,
   while ((run_ptr += size) <= end_ptr)
     {
       tmp_ptr = run_ptr - size;
-      while (cmp (run_ptr, tmp_ptr, arg) < 0)
+      while (tmp_ptr != base_ptr && cmp (run_ptr, tmp_ptr, arg) < 0)
         tmp_ptr -= size;
 
       tmp_ptr += size;