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Author SHA1 Message Date
Eric Dumazet
8fd57cfe08 tcp: properly terminate timers for kernel sockets 
[ Upstream commit 151c9c724d05d5b0dd8acd3e11cb69ef1f2dbada ]

We had various syzbot reports about tcp timers firing after
the corresponding netns has been dismantled.

Fortunately Josef Bacik could trigger the issue more often,
and could test a patch I wrote two years ago.

When TCP sockets are closed, we call inet_csk_clear_xmit_timers()
to 'stop' the timers.

inet_csk_clear_xmit_timers() can be called from any context,
including when socket lock is held.
This is the reason it uses sk_stop_timer(), aka del_timer().
This means that ongoing timers might finish much later.

For user sockets, this is fine because each running timer
holds a reference on the socket, and the user socket holds
a reference on the netns.

For kernel sockets, we risk that the netns is freed before
timer can complete, because kernel sockets do not hold
reference on the netns.

This patch adds inet_csk_clear_xmit_timers_sync() function
that using sk_stop_timer_sync() to make sure all timers
are terminated before the kernel socket is released.
Modules using kernel sockets close them in their netns exit()
handler.

Also add sock_not_owned_by_me() helper to get LOCKDEP
support : inet_csk_clear_xmit_timers_sync() must not be called
while socket lock is held.

It is very possible we can revert in the future commit
3a58f13a881e ("net: rds: acquire refcount on TCP sockets")
which attempted to solve the issue in rds only.
(net/smc/af_smc.c and net/mptcp/subflow.c have similar code)

We probably can remove the check_net() tests from
tcp_out_of_resources() and __tcp_close() in the future.

Reported-by: Josef Bacik <josef@toxicpanda.com>
Closes: https://lore.kernel.org/netdev/20240314210740.GA2823176@perftesting/
Fixes: 26abe14379f8 ("net: Modify sk_alloc to not reference count the netns of kernel sockets.")
Fixes: 8a68173691f0 ("net: sk_clone_lock() should only do get_net() if the parent is not a kernel socket")
Link: https://lore.kernel.org/bpf/CANn89i+484ffqb93aQm1N-tjxxvb3WDKX0EbD7318RwRgsatjw@mail.gmail.com/
Signed-off-by: Eric Dumazet <edumazet@google.com>
Tested-by: Josef Bacik <josef@toxicpanda.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Link: https://lore.kernel.org/r/20240322135732.1535772-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
 2024-11-19 09:22:44 +01:00
Zhengchao Shao
1b784270a1 tcp: make sure init the accept_queue's spinlocks once 
[ Upstream commit 198bc90e0e734e5f98c3d2833e8390cac3df61b2 ]

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>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20240118012019.1751966-1-shaozhengchao@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
 2024-11-18 12:12:59 +01:00
Gabriel2392
7ed7ee9edf Import A536BXXU9EXDC 2024-06-15 16:02:09 -03:00