diff options
| author | Vlad Buslov <vladbu@nvidia.com> | 2023-06-12 11:34:26 +0200 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-06-14 23:03:16 -0700 |
| commit | c9a82bec02c339cdda99b37c5e62b3b71fc4209c (patch) | |
| tree | 8e4ba3b2f1cc67a3d71520cb605e01aa84fe6648 | |
| parent | 24b454bc354ab7b1aa918a4fe3d7696516f592d4 (diff) | |
| download | linux-c9a82bec02c339cdda99b37c5e62b3b71fc4209c.tar.gz | |
net/sched: cls_api: Fix lockup on flushing explicitly created chain
Mingshuai Ren reports:
When a new chain is added by using tc, one soft lockup alarm will be
generated after delete the prio 0 filter of the chain. To reproduce
the problem, perform the following steps:
(1) tc qdisc add dev eth0 root handle 1: htb default 1
(2) tc chain add dev eth0
(3) tc filter del dev eth0 chain 0 parent 1: prio 0
(4) tc filter add dev eth0 chain 0 parent 1:
Fix the issue by accounting for additional reference to chains that are
explicitly created by RTM_NEWCHAIN message as opposed to implicitly by
RTM_NEWTFILTER message.
Fixes: 726d061286ce ("net: sched: prevent insertion of new classifiers during chain flush")
Reported-by: Mingshuai Ren <renmingshuai@huawei.com>
Closes: https://lore.kernel.org/lkml/87legswvi3.fsf@nvidia.com/T/
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Link: https://lore.kernel.org/r/20230612093426.2867183-1-vladbu@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
| -rw-r--r-- | net/sched/cls_api.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/net/sched/cls_api.c b/net/sched/cls_api.c index c877a6343fd47a..a193cc7b32418c 100644 --- a/net/sched/cls_api.c +++ b/net/sched/cls_api.c @@ -657,8 +657,8 @@ static void __tcf_chain_put(struct tcf_chain *chain, bool by_act, { struct tcf_block *block = chain->block; const struct tcf_proto_ops *tmplt_ops; + unsigned int refcnt, non_act_refcnt; bool free_block = false; - unsigned int refcnt; void *tmplt_priv; mutex_lock(&block->lock); @@ -678,13 +678,15 @@ static void __tcf_chain_put(struct tcf_chain *chain, bool by_act, * save these to temporary variables. */ refcnt = --chain->refcnt; + non_act_refcnt = refcnt - chain->action_refcnt; tmplt_ops = chain->tmplt_ops; tmplt_priv = chain->tmplt_priv; - /* The last dropped non-action reference will trigger notification. */ - if (refcnt - chain->action_refcnt == 0 && !by_act) { - tc_chain_notify_delete(tmplt_ops, tmplt_priv, chain->index, - block, NULL, 0, 0, false); + if (non_act_refcnt == chain->explicitly_created && !by_act) { + if (non_act_refcnt == 0) + tc_chain_notify_delete(tmplt_ops, tmplt_priv, + chain->index, block, NULL, 0, 0, + false); /* Last reference to chain, no need to lock. */ chain->flushing = false; } |