Re: WARNING: suspicious RCU usage in pid_task

[syzbot]

syzbot has bisected this bug to:

commit 23fb93a4d3f118a900790066d03368a296dce0d6
Author: David Ahern <dsahern@xxxxxxxxx>
Date:   Wed Apr 18 00:33:23 2018 +0000

    net/ipv6: Cleanup exception and cache route handling

bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1295147ae00000
start commit:   6f0d349d Merge git://git.kernel.org/pub/scm/linux/kernel/g..
git tree:       upstream
final crash:    https://syzkaller.appspot.com/x/report.txt?x=1195147ae00000
console output: https://syzkaller.appspot.com/x/log.txt?x=1695147ae00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=a63be0c83e84d370
dashboard link: https://syzkaller.appspot.com/bug?extid=c2d4c3ae3fd90bbaf059
syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=14f0a814400000
C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=16ce574c400000

Reported-by: syzbot+c2d4c3ae3fd90bbaf059@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 23fb93a4d3f1 ("net/ipv6: Cleanup exception and cache route handling")

For information about bisection process see: https://goo.gl/tpsmEJ#bisection