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From: David Miller <davem@davemloft.net>
To: lucien.xin@gmail.com
Cc: netdev@vger.kernel.org, linux-sctp@vger.kernel.org,
	edumazet@google.com, marcelo.leitner@gmail.com,
	nhorman@tuxdriver.com, dvyukov@google.com,
	syzkaller@googlegroups.com
Subject: Re: [PATCH net] sctp: not allow transport timeout value less than HZ/5 for hb_timer
Date: Tue, 05 Jun 2018 10:23:39 -0400 (EDT)	[thread overview]
Message-ID: <20180605.102339.1043965092278555314.davem@davemloft.net> (raw)
In-Reply-To: <97b99fac474db414ea8486a1fbd3a37dacd4b1b1.1528172218.git.lucien.xin@gmail.com>

From: Xin Long <lucien.xin@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+3dcd59a1f907245f891f@syzkaller.appspotmail.com
> Suggested-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
> Signed-off-by: Xin Long <lucien.xin@gmail.com>

Applied and queued up for -stable, thanks Xin.

      parent reply	other threads:[~2018-06-05 14:23 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-05  4:16 [PATCH net] sctp: not allow transport timeout value less than HZ/5 for hb_timer Xin Long
2018-06-05 10:27 ` Neil Horman
2018-06-05 14:23 ` David Miller [this message]

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