From: Eric Dumazet <eric.dumazet@gmail.com>
To: Vlad Buslov <vladbu@mellanox.com>, netdev@vger.kernel.org
Cc: jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us,
davem@davemloft.net
Subject: Re: [PATCH net v2 1/3] net: sched: sch_htb: don't call qdisc_put() while holding tree lock
Date: Thu, 19 Sep 2019 15:49:44 -0700 [thread overview]
Message-ID: <66e68933-a553-e078-b92b-6f629c740328@gmail.com> (raw)
In-Reply-To: <20190919201438.2383-2-vladbu@mellanox.com>
On 9/19/19 1:14 PM, Vlad Buslov wrote:
> Recent changes that removed rtnl dependency from rules update path of tc
> also made tcf_block_put() function sleeping. This function is called from
> ops->destroy() of several Qdisc implementations, which in turn is called by
> qdisc_put(). Some Qdiscs call qdisc_put() while holding sch tree spinlock,
> which results sleeping-while-atomic BUG.
>
Note that calling qdisc_put() while holding sch tree lock can also
trigger deadlocks.
For example sch_pie.c has a del_timer_sync() in pie_destroy(),
while the pie_timer() timer handler acquires the root_lock.
(there are other cases like that, SFQ for example)
next prev parent reply other threads:[~2019-09-19 22:49 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-19 20:14 [PATCH net v2 0/3] Fix Qdisc destroy issues caused by adding fine-grained locking to filter API Vlad Buslov
2019-09-19 20:14 ` [PATCH net v2 1/3] net: sched: sch_htb: don't call qdisc_put() while holding tree lock Vlad Buslov
2019-09-19 22:49 ` Eric Dumazet [this message]
2019-09-20 6:34 ` Vlad Buslov
2019-09-20 1:05 ` Cong Wang
2019-09-20 6:27 ` Vlad Buslov
2019-09-20 16:53 ` Cong Wang
2019-09-19 20:14 ` [PATCH net v2 2/3] net: sched: multiq: " Vlad Buslov
2019-09-19 20:14 ` [PATCH net v2 3/3] net: sched: sch_sfb: " Vlad Buslov
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