Hi, "Zhang, Qiang" <[email protected]> writes:
> ________________________________________ > 发件人: [email protected] <[email protected]> > 代表 syzbot <[email protected]> > 发送时间: 2020年7月29日 13:53 > 收件人: [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected]; [email protected]; > [email protected]; [email protected] > 主题: INFO: rcu detected stall in tc_modify_qdisc > > Hello, > > syzbot found the following issue on: > > HEAD commit: 181964e6 fix a braino in cmsghdr_from_user_compat_to_kern() > git tree: net > console output: https://syzkaller.appspot.com/x/log.txt?x=12925e38900000 > kernel config: https://syzkaller.appspot.com/x/.config?x=f87a5e4232fdb267 > dashboard link: https://syzkaller.appspot.com/bug?extid=9f78d5c664a8c33f4cce > compiler: gcc (GCC) 10.1.0-syz 20200507 > syz repro: > https://syzkaller.appspot.com/x/repro.syz?x=16587f8c900000 It seems that syzkaller is generating an schedule with too small intervals (3ns in this case) which causes a hrtimer busy-loop which starves other kernel threads. We could put some limits on the interval when running in software mode, but I don't like this too much, because we are talking about users with CAP_NET_ADMIN and they have easier ways to do bad things to the system. Cheers, -- Vinicius
