Hi, "Zhang, Qiang" <qiang.zh...@windriver.com> writes:
> ________________________________________ > 发件人: linux-kernel-ow...@vger.kernel.org <linux-kernel-ow...@vger.kernel.org> > 代表 syzbot <syzbot+9f78d5c664a8c33f4...@syzkaller.appspotmail.com> > 发送时间: 2020年7月29日 13:53 > 收件人: da...@davemloft.net; fweis...@gmail.com; j...@mojatatu.com; > j...@resnulli.us; linux-kernel@vger.kernel.org; mi...@kernel.org; > net...@vger.kernel.org; syzkaller-b...@googlegroups.com; t...@linutronix.de; > vinicius.go...@intel.com; xiyou.wangc...@gmail.com > 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
