Re: [PATCH net,v4] tcp: make sure init the accept_queue's spinlocks once

[Chen-Yu Tsai <wenst@chromium.org>]

Hi,

On Thu, Jan 18, 2024 at 09:20:19AM +0800, Zhengchao Shao wrote:
> When I run syz's reproduction C program locally, it causes the following
> issue:
> pvqspinlock: lock 0xffff9d181cd5c660 has corrupted value 0x0!
> WARNING: CPU: 19 PID: 21160 at __pv_queued_spin_unlock_slowpath (kernel/locking/qspinlock_paravirt.h:508)
> Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
> RIP: 0010:__pv_queued_spin_unlock_slowpath (kernel/locking/qspinlock_paravirt.h:508)
> Code: 73 56 3a ff 90 c3 cc cc cc cc 8b 05 bb 1f 48 01 85 c0 74 05 c3 cc cc cc cc 8b 17 48 89 fe 48 c7 c7
> 30 20 ce 8f e8 ad 56 42 ff <0f> 0b c3 cc cc cc cc 0f 0b 0f 1f 40 00 90 90 90 90 90 90 90 90 90
> RSP: 0018:ffffa8d200604cb8 EFLAGS: 00010282
> RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff9d1ef60e0908
> RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff9d1ef60e0900
> RBP: ffff9d181cd5c280 R08: 0000000000000000 R09: 00000000ffff7fff
> R10: ffffa8d200604b68 R11: ffffffff907dcdc8 R12: 0000000000000000
> R13: ffff9d181cd5c660 R14: ffff9d1813a3f330 R15: 0000000000001000
> FS:  00007fa110184640(0000) GS:ffff9d1ef60c0000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000020000000 CR3: 000000011f65e000 CR4: 00000000000006f0
> Call Trace:
> <IRQ>
>   _raw_spin_unlock (kernel/locking/spinlock.c:186)
>   inet_csk_reqsk_queue_add (net/ipv4/inet_connection_sock.c:1321)
>   inet_csk_complete_hashdance (net/ipv4/inet_connection_sock.c:1358)
>   tcp_check_req (net/ipv4/tcp_minisocks.c:868)
>   tcp_v4_rcv (net/ipv4/tcp_ipv4.c:2260)
>   ip_protocol_deliver_rcu (net/ipv4/ip_input.c:205)
>   ip_local_deliver_finish (net/ipv4/ip_input.c:234)
>   __netif_receive_skb_one_core (net/core/dev.c:5529)
>   process_backlog (./include/linux/rcupdate.h:779)
>   __napi_poll (net/core/dev.c:6533)
>   net_rx_action (net/core/dev.c:6604)
>   __do_softirq (./arch/x86/include/asm/jump_label.h:27)
>   do_softirq (kernel/softirq.c:454 kernel/softirq.c:441)
> </IRQ>
> <TASK>
>   __local_bh_enable_ip (kernel/softirq.c:381)
>   __dev_queue_xmit (net/core/dev.c:4374)
>   ip_finish_output2 (./include/net/neighbour.h:540 net/ipv4/ip_output.c:235)
>   __ip_queue_xmit (net/ipv4/ip_output.c:535)
>   __tcp_transmit_skb (net/ipv4/tcp_output.c:1462)
>   tcp_rcv_synsent_state_process (net/ipv4/tcp_input.c:6469)
>   tcp_rcv_state_process (net/ipv4/tcp_input.c:6657)
>   tcp_v4_do_rcv (net/ipv4/tcp_ipv4.c:1929)
>   __release_sock (./include/net/sock.h:1121 net/core/sock.c:2968)
>   release_sock (net/core/sock.c:3536)
>   inet_wait_for_connect (net/ipv4/af_inet.c:609)
>   __inet_stream_connect (net/ipv4/af_inet.c:702)
>   inet_stream_connect (net/ipv4/af_inet.c:748)
>   __sys_connect (./include/linux/file.h:45 net/socket.c:2064)
>   __x64_sys_connect (net/socket.c:2073 net/socket.c:2070 net/socket.c:2070)
>   do_syscall_64 (arch/x86/entry/common.c:51 arch/x86/entry/common.c:82)
>   entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:129)
>   RIP: 0033:0x7fa10ff05a3d
>   Code: 5b 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89
>   c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d ab a3 0e 00 f7 d8 64 89 01 48
>   RSP: 002b:00007fa110183de8 EFLAGS: 00000202 ORIG_RAX: 000000000000002a
>   RAX: ffffffffffffffda RBX: 0000000020000054 RCX: 00007fa10ff05a3d
>   RDX: 000000000000001c RSI: 0000000020000040 RDI: 0000000000000003
>   RBP: 00007fa110183e20 R08: 0000000000000000 R09: 0000000000000000
>   R10: 0000000000000000 R11: 0000000000000202 R12: 00007fa110184640
>   R13: 0000000000000000 R14: 00007fa10fe8b060 R15: 00007fff73e23b20
> </TASK>
> 
> The issue triggering process is analyzed as follows:
> Thread A                                       Thread B
> tcp_v4_rcv	//receive ack TCP packet       inet_shutdown
>   tcp_check_req                                  tcp_disconnect //disconnect sock
>   ...                                              tcp_set_state(sk, TCP_CLOSE)
>     inet_csk_complete_hashdance                ...
>       inet_csk_reqsk_queue_add                 inet_listen  //start listen
>         spin_lock(&queue->rskq_lock)             inet_csk_listen_start
>         ...                                        reqsk_queue_alloc
>         ...                                          spin_lock_init
>         spin_unlock(&queue->rskq_lock)	//warning
> 
> When the socket receives the ACK packet during the three-way handshake,
> it will hold spinlock. And then the user actively shutdowns the socket
> and listens to the socket immediately, the spinlock will be initialized.
> When the socket is going to release the spinlock, a warning is generated.
> Also the same issue to fastopenq.lock.
> 
> Move init spinlock to inet_create and inet_accept to make sure init the
> accept_queue's spinlocks once.
> 
> Fixes: fff1f3001cc5 ("tcp: add a spinlock to protect struct request_sock_queue")
> Fixes: 168a8f58059a ("tcp: TCP Fast Open Server - main code path")
> Reported-by: Ming Shu <sming56@aliyun.com>
> Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>

This patch causes a lockdep error for me on next-20240122 when SSHing
into my test device over IPv6. Reverting this patch gets rid of the
message, but that is probably not the correct fix.

Given that inet_listen is also used from net/ipv6/af_inet6.c, and
__inet_listen_sk is used from mptcp, inet_init_csk_locks() would need
to be called in a couple more places. I don't know much about the
networking stack, but I can try to come up with a patch.

Backtrace below:

INFO: trying to register non-static key.
The code is fine but needs lockdep annotation, or maybe
you didn't initialize this object before use?
turning off the locking correctness validator.
CPU: 0 PID: 0 Comm: swapper/0 Not tainted 6.8.0-rc1-next-20240122-01036-g319fbd8fc6d3 #147 2400bce4623c16f3873f828b5d429524a0849cd3
Hardware name: Google Krane Chromebook (DT)
Call trace:
dump_backtrace (arch/arm64/kernel/stacktrace.c:293) 
show_stack (arch/arm64/kernel/stacktrace.c:300) 
dump_stack_lvl (lib/dump_stack.c:107) 
dump_stack (lib/dump_stack.c:114) 
register_lock_class (kernel/locking/lockdep.c:977 kernel/locking/lockdep.c:1289) 
__lock_acquire (kernel/locking/lockdep.c:5014) 
lock_acquire (./arch/arm64/include/asm/percpu.h:40 kernel/locking/lockdep.c:467 kernel/locking/lockdep.c:5756 kernel/locking/lockdep.c:5719) 
_raw_spin_lock (./include/linux/spinlock_api_smp.h:134 kernel/locking/spinlock.c:154) 
inet_csk_complete_hashdance (net/ipv4/inet_connection_sock.c:1303 net/ipv4/inet_connection_sock.c:1355) 
tcp_check_req (net/ipv4/tcp_minisocks.c:653) 
tcp_v6_rcv (net/ipv6/tcp_ipv6.c:1837) 
ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:438) 
ip6_input_finish (./include/linux/rcupdate.h:779 net/ipv6/ip6_input.c:484) 
ip6_input (./include/linux/netfilter.h:314 ./include/linux/netfilter.h:308 net/ipv6/ip6_input.c:492) 
ip6_sublist_rcv_finish (net/ipv6/ip6_input.c:86 (discriminator 3)) 
ip6_sublist_rcv (net/ipv6/ip6_input.c:317) 
ipv6_list_rcv (net/ipv6/ip6_input.c:326) 
__netif_receive_skb_list_core (net/core/dev.c:5577 net/core/dev.c:5625) 
netif_receive_skb_list_internal (net/core/dev.c:5679 net/core/dev.c:5768) 
napi_complete_done (./include/linux/list.h:37 (discriminator 2) ./include/net/gro.h:440 (discriminator 2) ./include/net/gro.h:435 (discriminator 2) net/core/dev.c:6108 (discriminator 2)) 
r8152_poll (drivers/net/usb/r8152.c:2780 (discriminator 1)) r8152
__napi_poll.constprop.0 (net/core/dev.c:6576) 
net_rx_action (net/core/dev.c:6647 net/core/dev.c:6778) 
__do_softirq (./arch/arm64/include/asm/jump_label.h:21 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:554) 
____do_softirq (arch/arm64/kernel/irq.c:82) 
call_on_irq_stack (arch/arm64/kernel/entry.S:895) 
do_softirq_own_stack (arch/arm64/kernel/irq.c:87) 
__irq_exit_rcu (./arch/arm64/include/asm/percpu.h:44 kernel/softirq.c:612 kernel/softirq.c:634) 
irq_exit_rcu (kernel/softirq.c:646 (discriminator 4)) 
el1_interrupt (arch/arm64/kernel/entry-common.c:505 arch/arm64/kernel/entry-common.c:517) 
el1h_64_irq_handler (arch/arm64/kernel/entry-common.c:523) 
el1h_64_irq (arch/arm64/kernel/entry.S:594) 
arch_local_irq_enable (./arch/arm64/include/asm/irqflags.h:51) 
cpuidle_enter (drivers/cpuidle/cpuidle.c:388) 
do_idle (kernel/sched/idle.c:134 kernel/sched/idle.c:215 kernel/sched/idle.c:312) 
cpu_startup_entry (kernel/sched/idle.c:409) 
rest_init (./include/linux/rcupdate.h:751 (discriminator 1) init/main.c:701 (discriminator 1)) 
arch_call_rest_init+0x1c/0x28 
start_kernel (init/main.c:1023 (discriminator 1)) 
__primary_switched (arch/arm64/kernel/head.S:524) 


Regards
ChenYu

> ---
> v4: Add a helper to init accept_queue's spinlocks.
> v3: Move init spinlock to inet_create and inet_accept.
> v2: Add 'init_done' to make sure init the accept_queue's spinlocks once.
> ---
>  include/net/inet_connection_sock.h | 8 ++++++++
>  net/core/request_sock.c            | 3 ---
>  net/ipv4/af_inet.c                 | 3 +++
>  net/ipv4/inet_connection_sock.c    | 4 ++++
>  4 files changed, 15 insertions(+), 3 deletions(-)
> 
> diff --git a/include/net/inet_connection_sock.h b/include/net/inet_connection_sock.h
> index d0a2f827d5f2..9ab4bf704e86 100644
> --- a/include/net/inet_connection_sock.h
> +++ b/include/net/inet_connection_sock.h
> @@ -357,4 +357,12 @@ static inline bool inet_csk_has_ulp(const struct sock *sk)
>  	return inet_test_bit(IS_ICSK, sk) && !!inet_csk(sk)->icsk_ulp_ops;
>  }
>  
> +static inline void inet_init_csk_locks(struct sock *sk)
> +{
> +	struct inet_connection_sock *icsk = inet_csk(sk);
> +
> +	spin_lock_init(&icsk->icsk_accept_queue.rskq_lock);
> +	spin_lock_init(&icsk->icsk_accept_queue.fastopenq.lock);
> +}
> +
>  #endif /* _INET_CONNECTION_SOCK_H */
> diff --git a/net/core/request_sock.c b/net/core/request_sock.c
> index f35c2e998406..63de5c635842 100644
> --- a/net/core/request_sock.c
> +++ b/net/core/request_sock.c
> @@ -33,9 +33,6 @@
>  
>  void reqsk_queue_alloc(struct request_sock_queue *queue)
>  {
> -	spin_lock_init(&queue->rskq_lock);
> -
> -	spin_lock_init(&queue->fastopenq.lock);
>  	queue->fastopenq.rskq_rst_head = NULL;
>  	queue->fastopenq.rskq_rst_tail = NULL;
>  	queue->fastopenq.qlen = 0;
> diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c
> index 835f4f9d98d2..4e635dd3d3c8 100644
> --- a/net/ipv4/af_inet.c
> +++ b/net/ipv4/af_inet.c
> @@ -330,6 +330,9 @@ static int inet_create(struct net *net, struct socket *sock, int protocol,
>  	if (INET_PROTOSW_REUSE & answer_flags)
>  		sk->sk_reuse = SK_CAN_REUSE;
>  
> +	if (INET_PROTOSW_ICSK & answer_flags)
> +		inet_init_csk_locks(sk);
> +
>  	inet = inet_sk(sk);
>  	inet_assign_bit(IS_ICSK, sk, INET_PROTOSW_ICSK & answer_flags);
>  
> diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
> index 8e2eb1793685..459af1f89739 100644
> --- a/net/ipv4/inet_connection_sock.c
> +++ b/net/ipv4/inet_connection_sock.c
> @@ -727,6 +727,10 @@ struct sock *inet_csk_accept(struct sock *sk, int flags, int *err, bool kern)
>  	}
>  	if (req)
>  		reqsk_put(req);
> +
> +	if (newsk)
> +		inet_init_csk_locks(newsk);
> +
>  	return newsk;
>  out_err:
>  	newsk = NULL;
> -- 
> 2.34.1
>