From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jiri Pirko <jiri@resnulli.us>
Subject: Re: [PATCH net] net/sched: act_police: add missing spinlock
 initialization
Date: Wed, 21 Nov 2018 22:43:19 +0100
Message-ID: <20181121214319.GH2264@nanopsycho>
References: <070f7a50d9fe76cb459b28d03fa322ce3dd59cb1.1542819002.git.dcaratti@redhat.com>
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Cc: Eric Dumazet <edumazet@google.com>,
        Jamal Hadi Salim <jhs@mojatatu.com>,
        Cong Wang <xiyou.wangcong@gmail.com>,
        "David S. Miller" <davem@davemloft.net>, netdev@vger.kernel.org,
        Ivan Vecera <ivecera@redhat.com>
To: Davide Caratti <dcaratti@redhat.com>
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Wed, Nov 21, 2018 at 06:23:53PM CET, dcaratti@redhat.com wrote:
>commit f2cbd4852820 ("net/sched: act_police: fix race condition on state
>variables") introduces a new spinlock, but forgets its initialization.
>Ensure that tcf_police_init() initializes 'tcfp_lock' every time a 'police'
>action is newly created, to avoid the following lockdep splat:
>
> INFO: trying to register non-static key.
> the code is fine but needs lockdep annotation.
> turning off the locking correctness validator.
> <...>
> Call Trace:
>  dump_stack+0x85/0xcb
>  register_lock_class+0x581/0x590
>  __lock_acquire+0xd4/0x1330
>  ? tcf_police_init+0x2fa/0x650 [act_police]
>  ? lock_acquire+0x9e/0x1a0
>  lock_acquire+0x9e/0x1a0
>  ? tcf_police_init+0x2fa/0x650 [act_police]
>  ? tcf_police_init+0x55a/0x650 [act_police]
>  _raw_spin_lock_bh+0x34/0x40
>  ? tcf_police_init+0x2fa/0x650 [act_police]
>  tcf_police_init+0x2fa/0x650 [act_police]
>  tcf_action_init_1+0x384/0x4c0
>  tcf_action_init+0xf6/0x160
>  tcf_action_add+0x73/0x170
>  tc_ctl_action+0x122/0x160
>  rtnetlink_rcv_msg+0x2a4/0x490
>  ? netlink_deliver_tap+0x99/0x400
>  ? validate_linkmsg+0x370/0x370
>  netlink_rcv_skb+0x4d/0x130
>  netlink_unicast+0x196/0x230
>  netlink_sendmsg+0x2e5/0x3e0
>  sock_sendmsg+0x36/0x40
>  ___sys_sendmsg+0x280/0x2f0
>  ? _raw_spin_unlock+0x24/0x30
>  ? handle_pte_fault+0xafe/0xf30
>  ? find_held_lock+0x2d/0x90
>  ? syscall_trace_enter+0x1df/0x360
>  ? __sys_sendmsg+0x5e/0xa0
>  __sys_sendmsg+0x5e/0xa0
>  do_syscall_64+0x60/0x210
>  entry_SYSCALL_64_after_hwframe+0x49/0xbe
> RIP: 0033:0x7f1841c7cf10
> Code: c3 48 8b 05 82 6f 2c 00 f7 db 64 89 18 48 83 cb ff eb dd 0f 1f 80 00 00 00 00 83 3d 8d d0 2c 00 00 75 10 b8 2e 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 ae cc 00 00 48 89 04 24
> RSP: 002b:00007ffcf9df4d68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
> RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007f1841c7cf10
> RDX: 0000000000000000 RSI: 00007ffcf9df4dc0 RDI: 0000000000000003
> RBP: 000000005bf56105 R08: 0000000000000002 R09: 00007ffcf9df8edc
> R10: 00007ffcf9df47e0 R11: 0000000000000246 R12: 0000000000671be0
> R13: 00007ffcf9df4e84 R14: 0000000000000008 R15: 0000000000000000
>
>Fixes: f2cbd4852820 ("net/sched: act_police: fix race condition on state variables")
>Reported-by: Cong Wang <xiyou.wangcong@gmail.com>
>Signed-off-by: Davide Caratti <dcaratti@redhat.com>

Acked-by: Jiri Pirko <jiri@mellanox.com>