Re: WARNING: suspicious RCU usage in xfrm_alloc_userspi

[syzbot]

syzbot has bisected this bug to:

commit f10e0010fae8174dc20bdc872bcaa85baa925cb7
Author: Su Yanjun <suyj.fnst@xxxxxxxxxxxxxx>
Date:   Thu Mar 7 01:54:08 2019 +0000

    net: xfrm: Add '_rcu' tag for rcu protected pointer in netns_xfrm

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1644ec8b200000
start commit:   f10e0010 net: xfrm: Add '_rcu' tag for rcu protected point..
git tree:       linux-next
final crash:    https://syzkaller.appspot.com/x/report.txt?x=1544ec8b200000
console output: https://syzkaller.appspot.com/x/log.txt?x=1144ec8b200000
kernel config:  https://syzkaller.appspot.com/x/.config?x=59cd5d43b5df6955
dashboard link: https://syzkaller.appspot.com/bug?extid=59752237f7ab21c3f3c3
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14e70cb3200000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=17292127200000

Reported-by: syzbot+59752237f7ab21c3f3c3@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: f10e0010 ("net: xfrm: Add '_rcu' tag for rcu protected pointer in  
netns_xfrm")