This is a note to let you know that I've just added the patch titled net: sched: tbf: don't call qdisc_put() while holding tree lock to the 5.19-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: net-sched-tbf-don-t-call-qdisc_put-while-holding-tre.patch and it can be found in the queue-5.19 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit 7cba19da54c3420bf850b7d7ba098d2a63bdae85 Author: Zhengchao Shao <shaozhengchao@xxxxxxxxxx> Date: Fri Aug 26 09:39:30 2022 +0800 net: sched: tbf: don't call qdisc_put() while holding tree lock [ Upstream commit b05972f01e7d30419987a1f221b5593668fd6448 ] The issue is the same to commit c2999f7fb05b ("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: c266f64dbfa2 ("net: sched: protect block state with mutex") Signed-off-by: Zhengchao Shao <shaozhengchao@xxxxxxxxxx> Link: https://lore.kernel.org/r/20220826013930.340121-1-shaozhengchao@xxxxxxxxxx Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/net/sched/sch_tbf.c b/net/sched/sch_tbf.c index 72102277449e1..36079fdde2cb5 100644 --- a/net/sched/sch_tbf.c +++ b/net/sched/sch_tbf.c @@ -356,6 +356,7 @@ 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; @@ -447,7 +448,7 @@ 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; @@ -467,6 +468,7 @@ 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; tbf_offload_change(sch);