--- /dev/null
+Test script to reproduce the problem:
+
+#!/usr/bin/env perl
+$) = "2 2";
+print $!;
+
+Result from perl 5.28 under strace:
+
+setgroups(1, [2]) = 0
+setresgid(-1, 2, -1) = 0
+
+Result from perl 5.30 under strace:
+
+setgroups(1, [-1]) = -1 EINVAL (Invalid argument)
+setresgid(-1, 2, -1) = 0
+
+Patch which broke this upstream:
+https://perl5.git.perl.org/perl.git/commitdiff/5d4a52b5c68a11bfc97c2e24806993b84a61eade
+
+Issue is that the new function changes the endptr to the end of the
+scanned number and needs to be reset to the end of the string for
+each iteration of the loop.
+
+[YOCTO #13391]
+
+RP
+2019/6/14
+Upstream-Status: Pending
+
+Index: perl-5.30.0/mg.c
+===================================================================
+--- perl-5.30.0.orig/mg.c
++++ perl-5.30.0/mg.c
+@@ -3179,6 +3256,7 @@ Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
+ const char *p = SvPV_const(sv, len);
+ Groups_t *gary = NULL;
+ const char* endptr = p + len;
++ const char* realend = p + len;
+ UV uv;
+ #ifdef _SC_NGROUPS_MAX
+ int maxgrp = sysconf(_SC_NGROUPS_MAX);
+@@ -3209,6 +3287,7 @@ Perl_magic_set(pTHX_ SV *sv, MAGIC *mg)
+ Newx(gary, i + 1, Groups_t);
+ else
+ Renew(gary, i + 1, Groups_t);
++ endptr = realend;
+ if (grok_atoUV(p, &uv, &endptr))
+ gary[i] = (Groups_t)uv;
+ else {
