============================================
WARNING: possible recursive locking detected
6.12.0-rc2-syzkaller-00050-g5b7c893ed5ed #0 Not tainted
--------------------------------------------
syz.0.2422/22353 is trying to acquire lock:
ffff8880649355d8 (k-slock-AF_INET){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff8880649355d8 (k-slock-AF_INET){+.-.}-{2:2}, at: sk_clone_lock+0x2cd/0xf40 net/core/sock.c:2396
but task is already holding lock:
ffff888037670e98 (k-slock-AF_INET){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
ffff888037670e98 (k-slock-AF_INET){+.-.}-{2:2}, at: sk_clone_lock+0x2cd/0xf40 net/core/sock.c:2396
other info that might help us debug this:
Possible unsafe locking scenario:
CPU0
----
lock(k-slock-AF_INET);
lock(k-slock-AF_INET);
*** DEADLOCK ***
May be due to missing lock nesting notation
7 locks held by syz.0.2422/22353:
#0: ffff888064936258 (sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1609 [inline]
#0: ffff888064936258 (sk_lock-AF_INET){+.+.}-{0:0}, at: inet_stream_connect+0x50/0xa0 net/ipv4/af_inet.c:749
#1: ffff888037671bd8 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1609 [inline]
#1: ffff888037671bd8 (k-sk_lock-AF_INET){+.+.}-{0:0}, at: mptcp_connect+0x656/0xb20 net/mptcp/protocol.c:3760
#2: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
#2: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#2: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: __ip_queue_xmit+0x5f/0x1b80 net/ipv4/ip_output.c:471
#3: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
#3: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#3: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: ip_finish_output2+0x45f/0x1390 net/ipv4/ip_output.c:229
#4: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: local_lock_acquire include/linux/local_lock_internal.h:29 [inline]
#4: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: process_backlog+0x33b/0x15b0 net/core/dev.c:6107
#5: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:337 [inline]
#5: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#5: ffffffff8e937de0 (rcu_read_lock){....}-{1:2}, at: ip_local_deliver_finish+0x230/0x5f0 net/ipv4/ip_input.c:232
#6: ffff888037670e98 (k-slock-AF_INET){+.-.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]
#6: ffff888037670e98 (k-slock-AF_INET){+.-.}-{2:2}, at: sk_clone_lock+0x2cd/0xf40 net/core/sock.c:2396
stack backtrace:
CPU: 0 UID: 0 PID: 22353 Comm: syz.0.2422 Not tainted 6.12.0-rc2-syzkaller-00050-g5b7c893ed5ed #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
<IRQ>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_deadlock_bug+0x483/0x620 kernel/locking/lockdep.c:3037
check_deadlock kernel/locking/lockdep.c:3089 [inline]
validate_chain+0x15e2/0x5920 kernel/locking/lockdep.c:3891
__lock_acquire+0x1384/0x2050 kernel/locking/lockdep.c:5202
lock_acquire+0x1ed/0x550 kernel/locking/lockdep.c:5825
__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]
_raw_spin_lock+0x2e/0x40 kernel/locking/spinlock.c:154
spin_lock include/linux/spinlock.h:351 [inline]
sk_clone_lock+0x2cd/0xf40 net/core/sock.c:2396
mptcp_sk_clone_init+0x32/0x13c0 net/mptcp/protocol.c:3279
subflow_syn_recv_sock+0x931/0x1920 net/mptcp/subflow.c:878
tcp_check_req+0xfe4/0x1a20 net/ipv4/tcp_minisocks.c:858
tcp_v4_rcv+0x1c3e/0x37f0 net/ipv4/tcp_ipv4.c:2271
ip_protocol_deliver_rcu+0x22e/0x440 net/ipv4/ip_input.c:205
ip_local_deliver_finish+0x341/0x5f0 net/ipv4/ip_input.c:233
NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
__netif_receive_skb_one_core net/core/dev.c:5666 [inline]
__netif_receive_skb+0x2bf/0x650 net/core/dev.c:5779
process_backlog+0x662/0x15b0 net/core/dev.c:6111
__napi_poll+0xcb/0x490 net/core/dev.c:6775
napi_poll net/core/dev.c:6844 [inline]
net_rx_action+0x89b/0x1240 net/core/dev.c:6966
handle_softirqs+0x2c5/0x980 kernel/softirq.c:554
do_softirq+0x11b/0x1e0 kernel/softirq.c:455
</IRQ>
<TASK>
__local_bh_enable_ip+0x1bb/0x200 kernel/softirq.c:382
local_bh_enable include/linux/bottom_half.h:33 [inline]
rcu_read_unlock_bh include/linux/rcupdate.h:919 [inline]
__dev_queue_xmit+0x171d/0x3ed0 net/core/dev.c:4455
dev_queue_xmit include/linux/netdevice.h:3094 [inline]
neigh_hh_output include/net/neighbour.h:526 [inline]
neigh_output include/net/neighbour.h:540 [inline]
ip_finish_output2+0xd41/0x1390 net/ipv4/ip_output.c:236
ip_local_out net/ipv4/ip_output.c:130 [inline]
__ip_queue_xmit+0x118c/0x1b80 net/ipv4/ip_output.c:536
__tcp_transmit_skb+0x2544/0x3b30 net/ipv4/tcp_output.c:1466
tcp_rcv_synsent_state_process net/ipv4/tcp_input.c:6549 [inline]
tcp_rcv_state_process+0x2c32/0x4570 net/ipv4/tcp_input.c:6736
tcp_v4_do_rcv+0x77d/0xc70 net/ipv4/tcp_ipv4.c:1938
sk_backlog_rcv include/net/sock.h:1113 [inline]
__release_sock+0x214/0x350 net/core/sock.c:3072
release_sock+0x61/0x1f0 net/core/sock.c:3626
mptcp_connect+0x7e4/0xb20 net/mptcp/protocol.c:3782
__inet_stream_connect+0x262/0xf30 net/ipv4/af_inet.c:679
inet_stream_connect+0x65/0xa0 net/ipv4/af_inet.c:750
__sys_connect_file net/socket.c:2066 [inline]
__sys_connect+0x2d1/0x300 net/socket.c:2083
__do_sys_connect net/socket.c:2093 [inline]
__se_sys_connect net/socket.c:2090 [inline]
__x64_sys_connect+0x7a/0x90 net/socket.c:2090
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f07fed7dff9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 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 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f07ffb45038 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 00007f07fef36130 RCX: 00007f07fed7dff9
RDX: 0000000000000010 RSI: 0000000020000000 RDI: 000000000000000b
RBP: 00007f07fedf0296 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f07fef36130 R15: 00007f07ff05fa28
</TASK>