From: Xin Long <lucien....@gmail.com> Date: Tue, 5 Jun 2018 12:16:58 +0800
> syzbot reported a rcu_sched self-detected stall on CPU which is caused > by too small value set on rto_min with SCTP_RTOINFO sockopt. With this > value, hb_timer will get stuck there, as in its timer handler it starts > this timer again with this value, then goes to the timer handler again. > > This problem is there since very beginning, and thanks to Eric for the > reproducer shared from a syzbot mail. > > This patch fixes it by not allowing sctp_transport_timeout to return a > smaller value than HZ/5 for hb_timer, which is based on TCP's min rto. > > Note that it doesn't fix this issue by limiting rto_min, as some users > are still using small rto and no proper value was found for it yet. > > Reported-by: syzbot+3dcd59a1f907245f8...@syzkaller.appspotmail.com > Suggested-by: Marcelo Ricardo Leitner <marcelo.leit...@gmail.com> > Signed-off-by: Xin Long <lucien....@gmail.com> Applied and queued up for -stable, thanks Xin.
