On 2019/08/03 14:36, Vlad Buslov wrote:
> Recently implemented support for police action in flow_offload infra leads
> to following rcu usage warning:
>
> [ 1925.881092] =============================
> [ 1925.881094] WARNING: suspicious RCU usage
> [ 1925.881098] 5.3.0-rc1+ #574 Not tainted
> [ 1925.881100] -----------------------------
> [ 1925.881104] include/net/tc_act/tc_police.h:57 suspicious
> rcu_dereference_check() usage!
> [ 1925.881106]
> other info that might help us debug this:
>
> [ 1925.881109]
> rcu_scheduler_active = 2, debug_locks = 1
> [ 1925.881112] 1 lock held by tc/18591:
> [ 1925.881115] #0: 00000000b03cb918 (rtnl_mutex){+.+.}, at:
> tc_new_tfilter+0x47c/0x970
> [ 1925.881124]
> stack backtrace:
> [ 1925.881127] CPU: 2 PID: 18591 Comm: tc Not tainted 5.3.0-rc1+ #574
> [ 1925.881130] Hardware name: Supermicro SYS-2028TP-DECR/X10DRT-P, BIOS 2.0b
> 03/30/2017
> [ 1925.881132] Call Trace:
> [ 1925.881138] dump_stack+0x85/0xc0
> [ 1925.881145] tc_setup_flow_action+0x1771/0x2040
> [ 1925.881155] fl_hw_replace_filter+0x11f/0x2e0 [cls_flower]
> [ 1925.881175] fl_change+0xd24/0x1b30 [cls_flower]
> [ 1925.881200] tc_new_tfilter+0x3e0/0x970
> [ 1925.881231] ? tc_del_tfilter+0x720/0x720
> [ 1925.881243] rtnetlink_rcv_msg+0x389/0x4b0
> [ 1925.881250] ? netlink_deliver_tap+0x95/0x400
> [ 1925.881257] ? rtnl_dellink+0x2d0/0x2d0
> [ 1925.881264] netlink_rcv_skb+0x49/0x110
> [ 1925.881275] netlink_unicast+0x171/0x200
> [ 1925.881284] netlink_sendmsg+0x224/0x3f0
> [ 1925.881299] sock_sendmsg+0x5e/0x60
> [ 1925.881305] ___sys_sendmsg+0x2ae/0x330
> [ 1925.881309] ? task_work_add+0x43/0x50
> [ 1925.881314] ? fput_many+0x45/0x80
> [ 1925.881329] ? __lock_acquire+0x248/0x1930
> [ 1925.881342] ? find_held_lock+0x2b/0x80
> [ 1925.881347] ? task_work_run+0x7b/0xd0
> [ 1925.881359] __sys_sendmsg+0x59/0xa0
> [ 1925.881375] do_syscall_64+0x5c/0xb0
> [ 1925.881381] entry_SYSCALL_64_after_hwframe+0x49/0xbe
> [ 1925.881384] RIP: 0033:0x7feb245047b8
> [ 1925.881388] Code: 89 02 48 c7 c0 ff ff ff ff eb bb 0f 1f 80 00 00 00 00 f3
> 0f 1e fa 48 8d 05 65 8f 0c 00 8b 00 85 c0 75 17 b8 2e 00 00 00 0f 05 <48> 3d
> 00 f0 ff ff 77 58 c3 0f 1f 80 00 00 00 00 48 83
> ec 28 89 54
> [ 1925.881391] RSP: 002b:00007ffc2d2a5788 EFLAGS: 00000246 ORIG_RAX:
> 000000000000002e
> [ 1925.881395] RAX: ffffffffffffffda RBX: 000000005d4497ed RCX:
> 00007feb245047b8
> [ 1925.881398] RDX: 0000000000000000 RSI: 00007ffc2d2a57f0 RDI:
> 0000000000000003
> [ 1925.881400] RBP: 0000000000000000 R08: 0000000000000001 R09:
> 0000000000000006
> [ 1925.881403] R10: 0000000000404ec2 R11: 0000000000000246 R12:
> 0000000000000001
> [ 1925.881406] R13: 0000000000480640 R14: 0000000000000012 R15:
> 0000000000000001
>
> Change tcf_police_rate_bytes_ps() and tcf_police_tcfp_burst() helpers to
> allow using them from both rtnl and rcu protected contexts.
>
> Fixes: 8c8cfc6ed274 ("net/sched: add police action to the hardware
> intermediate representation")
> Signed-off-by: Vlad Buslov <[email protected]>
Thank you Vlad.
Reviewed-by: Pieter Jansen van Vuuren <[email protected]>
