diff --git a/ChangeLog b/ChangeLog
index ed2f2695..2a38f8d7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -8,4 +8,7 @@ Version ????
 
 	Put most of the Debian diffs in.
 
+	ps no longer crashes if System.map is %1024. Debian #109237
+	(Thanks Colin Walters)
+
 
diff --git a/proc/ksym.c b/proc/ksym.c
index 8925bd5a..4549ffaa 100644
--- a/proc/ksym.c
+++ b/proc/ksym.c
@@ -356,7 +356,7 @@ static int sysmap_mmap(const char *filename, void (*message)(const char *, ...))
     sysmap_index = vp;
     for(;;){
       char *vstart;
-      if(!*endp){                /* if we reached the end */
+      if(endp - sysmap_data >= sbuf.st_size){   /* if we reached the end */
         int i = VCNT;            /* check VCNT times to verify this file */
         if(*Version) goto bad_version;
         if(!ksyms_index) return 1; /* if can not verify, assume success */