From: Xin Long lucien.xin@gmail.com
[ Upstream commit a81047154e7ce4eb8769d5d21adcbc9693542a79 ]
flow_offload_queue_work() can be called in workqueue without bh disabled, like the call trace showed in my act_ct testing, calling NF_FLOW_TABLE_STAT_INC() there would cause a call trace:
BUG: using __this_cpu_add() in preemptible [00000000] code: kworker/u4:0/138560 caller is flow_offload_queue_work+0xec/0x1b0 [nf_flow_table] Workqueue: act_ct_workqueue tcf_ct_flow_table_cleanup_work [act_ct] Call Trace: <TASK> dump_stack_lvl+0x33/0x46 check_preemption_disabled+0xc3/0xf0 flow_offload_queue_work+0xec/0x1b0 [nf_flow_table] nf_flow_table_iterate+0x138/0x170 [nf_flow_table] nf_flow_table_free+0x140/0x1a0 [nf_flow_table] tcf_ct_flow_table_cleanup_work+0x2f/0x2b0 [act_ct] process_one_work+0x6a3/0x1030 worker_thread+0x8a/0xdf0
This patch fixes it by using NF_FLOW_TABLE_STAT_INC_ATOMIC() instead in flow_offload_queue_work().
Note that for FLOW_CLS_REPLACE branch in flow_offload_queue_work(), it may not be called in preemptible path, but it's good to use NF_FLOW_TABLE_STAT_INC_ATOMIC() for all cases in flow_offload_queue_work().
Fixes: b038177636f8 ("netfilter: nf_flow_table: count pending offload workqueue tasks") Signed-off-by: Xin Long lucien.xin@gmail.com Signed-off-by: Pablo Neira Ayuso pablo@netfilter.org Signed-off-by: Sasha Levin sashal@kernel.org --- net/netfilter/nf_flow_table_offload.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/net/netfilter/nf_flow_table_offload.c b/net/netfilter/nf_flow_table_offload.c index 00b522890d77..0fdcdb2c9ae4 100644 --- a/net/netfilter/nf_flow_table_offload.c +++ b/net/netfilter/nf_flow_table_offload.c @@ -997,13 +997,13 @@ static void flow_offload_queue_work(struct flow_offload_work *offload) struct net *net = read_pnet(&offload->flowtable->net);
if (offload->cmd == FLOW_CLS_REPLACE) { - NF_FLOW_TABLE_STAT_INC(net, count_wq_add); + NF_FLOW_TABLE_STAT_INC_ATOMIC(net, count_wq_add); queue_work(nf_flow_offload_add_wq, &offload->work); } else if (offload->cmd == FLOW_CLS_DESTROY) { - NF_FLOW_TABLE_STAT_INC(net, count_wq_del); + NF_FLOW_TABLE_STAT_INC_ATOMIC(net, count_wq_del); queue_work(nf_flow_offload_del_wq, &offload->work); } else { - NF_FLOW_TABLE_STAT_INC(net, count_wq_stats); + NF_FLOW_TABLE_STAT_INC_ATOMIC(net, count_wq_stats); queue_work(nf_flow_offload_stats_wq, &offload->work); } }