Re: [PATCH] net: openvswitch: silence suspicious RCU usage warning

From: Eelco Chaudron
Date: Wed Aug 05 2020 - 15:22:08 EST




On 5 Aug 2020, at 9:19, xiangxia.m.yue@xxxxxxxxx wrote:

From: Tonghao Zhang <xiangxia.m.yue@xxxxxxxxx>

ovs_flow_tbl_destroy always is called from RCU callback
or error path. It is no need to check if rcu_read_lock
or lockdep_ovsl_is_held was held.

ovs_dp_cmd_fill_info always is called with ovs_mutex,
So use the rcu_dereference_ovsl instead of rcu_dereference
in ovs_flow_tbl_masks_cache_size.

Fixes: 9bf24f594c6a ("net: openvswitch: make masks cache size configurable")
Cc: Eelco Chaudron <echaudro@xxxxxxxxxx>
Reported-by: syzbot+c0eb9e7cdde04e4eb4be@xxxxxxxxxxxxxxxxxxxxxxxxx
Reported-by: syzbot+f612c02823acb02ff9bc@xxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Tonghao Zhang <xiangxia.m.yue@xxxxxxxxx>

Thanks for fixing this, I was (am) on PTO so did not notice it earlier!

Cheers,

Eelco