---
 free.c         |   19 ++++++++++++++++---
 proc/sysinfo.c |    5 ++++-
 2 files changed, 20 insertions(+), 4 deletions(-)

--- free.c
+++ free.c	2021-02-10 09:58:35.409695062 +0000
@@ -134,7 +134,7 @@ static const char *scale_size(unsigned l
 		if (args.exponent > 1) {
 			/* In desired scale. */
 			snprintf(buf, sizeof(buf), "%ld",
-                 (long int)((size * 1024.0) / power(base, args.exponent-1))
+                 (long int)(((long long int)size * 1024) / power(base, args.exponent-1))
 			    );
 			return buf;
 		}
@@ -381,15 +381,28 @@ int main(int argc, char **argv)
 		 * to print the high info, even if it is zero.
 		 */
 		if (flags & FREE_LOHI) {
+			unsigned long kb_low_used;
+			unsigned long kb_high_used;
+
+			if (kb_low_total > kb_low_free)
+				kb_low_used = kb_low_total - kb_low_free;
+			else
+				kb_low_used = 0;
+
+			if (kb_high_total > kb_high_free)
+				kb_high_used = kb_high_total - kb_high_free;
+			else
+				kb_high_used = 0;
+
 			printf("%-9s", _("Low:"));
 			printf("%11s", scale_size(kb_low_total, flags, args));
-			printf(" %11s", scale_size(kb_low_total - kb_low_free, flags, args));
+			printf(" %11s", scale_size(kb_low_used, flags, args));
 			printf(" %11s", scale_size(kb_low_free, flags, args));
 			printf("\n");
 
 			printf("%-9s", _("High:"));
 			printf("%11s", scale_size(kb_high_total, flags, args));
-			printf(" %11s", scale_size(kb_high_total - kb_high_free, flags, args));
+			printf(" %11s", scale_size(kb_high_used, flags, args));
 			printf(" %11s", scale_size(kb_high_free, flags, args));
 			printf("\n");
 		}
--- proc/sysinfo.c
+++ proc/sysinfo.c	2021-02-10 10:00:35.227385913 +0000
@@ -783,7 +783,10 @@ nextline:
   kb_main_cached = kb_page_cache + kb_slab_reclaimable;
   if ((ev=getenv("PS_FULL_CACHE")))
     kb_main_cached += kb_swap_cached + kb_nfs_unstable;
-  kb_swap_used = kb_swap_total - kb_swap_free;
+  if (kb_swap_total > kb_swap_free)
+    kb_swap_used = kb_swap_total - kb_swap_free;
+  else
+    kb_swap_used = 0;
 
   /* if kb_main_available is greater than kb_main_total or our calculation of
      mem_used overflows, that's symptomatic of running within a lxc container