img: Operation not permitted issue when building on Fedora 28

Dockerfile:

FROM docker.io/library/alpine:latest
RUN echo hi

Using compiled runc binary from @AkihiroSuda 's demo-rootless branch

sub uid/gid file:

test (aws:rean-gov-sd)(kc)$ cat /etc/subuid
frezbo:100000:65536
test (aws:rean-gov-sd)(kc)$ cat /etc/subgid
frezbo:100000:65536
test (aws:rean-gov-sd)(kc)$

img build o/p:

test (aws:rean-gov-sd)(kc)$ img build -backend native -d -t hello -f  Dockerfile  .
Building docker.io/library/hello:latest
Setting up the rootfs... this may take a bit.
DEBU[0000] serving grpc connection                      
DEBU[0000] new ref for local: bt8npmb4ra0fufx6jmf84es2t 
DEBU[0000] new ref for local: r8q0jj3mqduet41nfj42u1g1f 
DEBU[0000] diffcopy took: 826.419µs                     
DEBU[0000] saved bt8npmb4ra0fufx6jmf84es2t as local.sharedKey:context:.dockerignore: 
DEBU[0000] diffcopy took: 1.040244ms                    
DEBU[0000] saved r8q0jj3mqduet41nfj42u1g1f as local.sharedKey:dockerfile:Dockerfile: 
solving failed: operation not permitted

This is what I saw in strace:

test (aws:rean-gov-sd)(kc)$ strace img build -d -t hello -f  Dockerfile  . 2>&1 | grep -i operation
epoll_ctl(4, EPOLL_CTL_ADD, 5, {EPOLLIN|EPOLLOUT|EPOLLRDHUP|EPOLLET, {u32=156319752, u64=140016090169352}}) = -1 EPERM (Operation not permitted)
epoll_ctl(4, EPOLL_CTL_DEL, 5, 0xc4201cbba4) = -1 EPERM (Operation not permitted)
wait4(-2937, solving failed: operation not permitted
test (aws:rean-gov-sd)(kc)$ 

OS info:

test (aws:rean-gov-sd)(kc)$ cat /etc/*-release
Fedora release 28 (Twenty Eight)
NAME=Fedora
VERSION="28 (Workstation Edition)"
ID=fedora
VERSION_ID=28
PLATFORM_ID="platform:f28"
PRETTY_NAME="Fedora 28 (Workstation Edition)"
ANSI_COLOR="0;34"
CPE_NAME="cpe:/o:fedoraproject:fedora:28"
HOME_URL="https://fedoraproject.org/"
SUPPORT_URL="https://fedoraproject.org/wiki/Communicating_and_getting_help"
BUG_REPORT_URL="https://bugzilla.redhat.com/"
REDHAT_BUGZILLA_PRODUCT="Fedora"
REDHAT_BUGZILLA_PRODUCT_VERSION=28
REDHAT_SUPPORT_PRODUCT="Fedora"
REDHAT_SUPPORT_PRODUCT_VERSION=28
PRIVACY_POLICY_URL="https://fedoraproject.org/wiki/Legal:PrivacyPolicy"
VARIANT="Workstation Edition"
VARIANT_ID=workstation
Fedora release 28 (Twenty Eight)
Fedora release 28 (Twenty Eight)
test (aws:rean-gov-sd)(kc)$ 

Kernel info:

test (aws:rean-gov-sd)(kc)$ uname -a
Linux localhost.localdomain 4.16.8-300.fc28.x86_64 #1 SMP Wed May 9 20:23:40 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
test (aws:rean-gov-sd)(kc)$ 

Will be happy to provide any more extra info