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Commit fffa19b5 authored by Zhengchao Shao's avatar Zhengchao Shao Committed by Greg Kroah-Hartman
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net: sched: tbf: don't call qdisc_put() while holding tree lock 



[ Upstream commit b05972f01e7d30419987a1f221b5593668fd6448 ]

The issue is the same to commit c2999f7f ("net: sched: multiq: don't
call qdisc_put() while holding tree lock"). Qdiscs call qdisc_put() while
holding sch tree spinlock, which results sleeping-while-atomic BUG.

Fixes: c266f64d ("net: sched: protect block state with mutex")
Signed-off-by: default avatarZhengchao Shao <shaozhengchao@huawei.com>
Link: https://lore.kernel.org/r/20220826013930.340121-1-shaozhengchao@huawei.com


Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent e1ba258d

net/sched/sch_tbf.c

+3 −1
Original line number Diff line number Diff line
@@ -297,6 +297,7 @@ static int tbf_change(struct Qdisc *sch, struct nlattr *opt, 
	struct nlattr *tb[TCA_TBF_MAX + 1];

	struct tc_tbf_qopt *qopt;

	struct Qdisc *child = NULL;

	struct Qdisc *old = NULL;

	struct psched_ratecfg rate;

	struct psched_ratecfg peak;

	u64 max_size;
@@ -388,7 +389,7 @@ static int tbf_change(struct Qdisc *sch, struct nlattr *opt, 
	sch_tree_lock(sch);

	if (child) {

		qdisc_tree_flush_backlog(q->qdisc);

		qdisc_put(q->qdisc);

		old = q->qdisc;

		q->qdisc = child;

	}

	q->limit = qopt->limit;
@@ -408,6 +409,7 @@ static int tbf_change(struct Qdisc *sch, struct nlattr *opt, 
	memcpy(&q->peak, &peak, sizeof(struct psched_ratecfg));



	sch_tree_unlock(sch);

	qdisc_put(old);

	err = 0;

done:

	return err;