======================================================
WARNING: possible circular locking dependency detected
5.15.173-syzkaller #0 Not tainted
------------------------------------------------------
syz.1.181/4553 is trying to acquire lock:
ffff0000d9e70d20 (sk_lock-AF_INET6){+.+.}-{0:0}, at: inet_sk_diag_fill+0xcb8/0x17b4 net/ipv4/inet_diag.c:342

but task is already holding lock:
ffff0000c560de48 (&h->lhash2[i].lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
ffff0000c560de48 (&h->lhash2[i].lock){+.+.}-{2:2}, at: mptcp_diag_dump_listeners net/mptcp/mptcp_diag.c:95 [inline]
ffff0000c560de48 (&h->lhash2[i].lock){+.+.}-{2:2}, at: mptcp_diag_dump+0x7b0/0x10dc net/mptcp/mptcp_diag.c:194

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&h->lhash2[i].lock){+.+.}-{2:2}:
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0xb0/0x10c kernel/locking/spinlock.c:154
       spin_lock include/linux/spinlock.h:363 [inline]
       __inet_hash+0xd0/0x8e0 net/ipv4/inet_hashtables.c:613
       inet6_hash+0x74/0x9c net/ipv6/inet6_hashtables.c:343
       inet_csk_listen_start+0x1e8/0x2cc net/ipv4/inet_connection_sock.c:1115
       inet_listen+0x258/0x6d4 net/ipv4/af_inet.c:231
       __sys_listen+0x1ac/0x21c net/socket.c:1754
       __do_sys_listen net/socket.c:1763 [inline]
       __se_sys_listen net/socket.c:1761 [inline]
       __arm64_sys_listen+0x5c/0x74 net/socket.c:1761
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

-> #0 (sk_lock-AF_INET6){+.+.}-{0:0}:
       check_prev_add kernel/locking/lockdep.c:3053 [inline]
       check_prevs_add kernel/locking/lockdep.c:3172 [inline]
       validate_chain kernel/locking/lockdep.c:3788 [inline]
       __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
       lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
       lock_sock_fast include/net/sock.h:1710 [inline]
       mptcp_diag_get_info+0x208/0x8a0 net/mptcp/mptcp_diag.c:224
       inet_sk_diag_fill+0xcb8/0x17b4 net/ipv4/inet_diag.c:342
       sk_diag_dump net/mptcp/mptcp_diag.c:24 [inline]
       mptcp_diag_dump_listeners net/mptcp/mptcp_diag.c:122 [inline]
       mptcp_diag_dump+0xb4c/0x10dc net/mptcp/mptcp_diag.c:194
       __inet_diag_dump+0x1e8/0x33c net/ipv4/inet_diag.c:1179
       inet_diag_dump+0x4c/0x5c net/ipv4/inet_diag.c:1198
       netlink_dump+0x4a8/0xad0 net/netlink/af_netlink.c:2280
       __netlink_dump_start+0x474/0x6d4 net/netlink/af_netlink.c:2383
       netlink_dump_start include/linux/netlink.h:258 [inline]
       inet_diag_handler_cmd+0x1a8/0x274 net/ipv4/inet_diag.c:1344
       sock_diag_rcv_msg+0x174/0x39c
       netlink_rcv_skb+0x20c/0x3b8 net/netlink/af_netlink.c:2504
       sock_diag_rcv+0x3c/0x54 net/core/sock_diag.c:276
       netlink_unicast_kernel net/netlink/af_netlink.c:1326 [inline]
       netlink_unicast+0x664/0x938 net/netlink/af_netlink.c:1352
       netlink_sendmsg+0x844/0xb38 net/netlink/af_netlink.c:1920
       sock_sendmsg_nosec net/socket.c:704 [inline]
       __sock_sendmsg net/socket.c:716 [inline]
       sock_write_iter+0x2b0/0x3f8 net/socket.c:1079
       do_iter_readv_writev+0x420/0x5f8
       do_iter_write+0x1b8/0x66c fs/read_write.c:855
       vfs_writev fs/read_write.c:928 [inline]
       do_writev+0x220/0x3ec fs/read_write.c:971
       __do_sys_writev fs/read_write.c:1044 [inline]
       __se_sys_writev fs/read_write.c:1041 [inline]
       __arm64_sys_writev+0x80/0x94 fs/read_write.c:1041
       __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
       invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
       el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
       do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
       el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
       el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
       el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&h->lhash2[i].lock);
                               lock(sk_lock-AF_INET6);
                               lock(&h->lhash2[i].lock);
  lock(sk_lock-AF_INET6);

 *** DEADLOCK ***

6 locks held by syz.1.181/4553:
 #0: ffff800016cac848 (sock_diag_mutex){+.+.}-{3:3}, at: sock_diag_rcv+0x2c/0x54 net/core/sock_diag.c:275
 #1: ffff800016cac6a8 (sock_diag_table_mutex){+.+.}-{3:3}, at: __sock_diag_cmd net/core/sock_diag.c:229 [inline]
 #1: ffff800016cac6a8 (sock_diag_table_mutex){+.+.}-{3:3}, at: sock_diag_rcv_msg+0x220/0x39c net/core/sock_diag.c:265
 #2: ffff0000cb1f8690 (nlk_cb_mutex-SOCK_DIAG){+.+.}-{3:3}, at: __netlink_dump_start+0x108/0x6d4 net/netlink/af_netlink.c:2349
 #3: ffff800016d85ca8 (inet_diag_table_mutex){+.+.}-{3:3}, at: inet_diag_lock_handler net/ipv4/inet_diag.c:63 [inline]
 #3: ffff800016d85ca8 (inet_diag_table_mutex){+.+.}-{3:3}, at: __inet_diag_dump+0x17c/0x33c net/ipv4/inet_diag.c:1177
 #4: ffff800014d322e0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:311
 #5: ffff0000c560de48 (&h->lhash2[i].lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
 #5: ffff0000c560de48 (&h->lhash2[i].lock){+.+.}-{2:2}, at: mptcp_diag_dump_listeners net/mptcp/mptcp_diag.c:95 [inline]
 #5: ffff0000c560de48 (&h->lhash2[i].lock){+.+.}-{2:2}, at: mptcp_diag_dump+0x7b0/0x10dc net/mptcp/mptcp_diag.c:194

stack backtrace:
CPU: 0 PID: 4553 Comm: syz.1.181 Not tainted 5.15.173-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 print_circular_bug+0x150/0x1b8 kernel/locking/lockdep.c:2011
 check_noncircular+0x2cc/0x378 kernel/locking/lockdep.c:2133
 check_prev_add kernel/locking/lockdep.c:3053 [inline]
 check_prevs_add kernel/locking/lockdep.c:3172 [inline]
 validate_chain kernel/locking/lockdep.c:3788 [inline]
 __lock_acquire+0x32d4/0x7638 kernel/locking/lockdep.c:5012
 lock_acquire+0x240/0x77c kernel/locking/lockdep.c:5623
 lock_sock_fast include/net/sock.h:1710 [inline]
 mptcp_diag_get_info+0x208/0x8a0 net/mptcp/mptcp_diag.c:224
 inet_sk_diag_fill+0xcb8/0x17b4 net/ipv4/inet_diag.c:342
 sk_diag_dump net/mptcp/mptcp_diag.c:24 [inline]
 mptcp_diag_dump_listeners net/mptcp/mptcp_diag.c:122 [inline]
 mptcp_diag_dump+0xb4c/0x10dc net/mptcp/mptcp_diag.c:194
 __inet_diag_dump+0x1e8/0x33c net/ipv4/inet_diag.c:1179
 inet_diag_dump+0x4c/0x5c net/ipv4/inet_diag.c:1198
 netlink_dump+0x4a8/0xad0 net/netlink/af_netlink.c:2280
 __netlink_dump_start+0x474/0x6d4 net/netlink/af_netlink.c:2383
 netlink_dump_start include/linux/netlink.h:258 [inline]
 inet_diag_handler_cmd+0x1a8/0x274 net/ipv4/inet_diag.c:1344
 sock_diag_rcv_msg+0x174/0x39c
 netlink_rcv_skb+0x20c/0x3b8 net/netlink/af_netlink.c:2504
 sock_diag_rcv+0x3c/0x54 net/core/sock_diag.c:276
 netlink_unicast_kernel net/netlink/af_netlink.c:1326 [inline]
 netlink_unicast+0x664/0x938 net/netlink/af_netlink.c:1352
 netlink_sendmsg+0x844/0xb38 net/netlink/af_netlink.c:1920
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 sock_write_iter+0x2b0/0x3f8 net/socket.c:1079
 do_iter_readv_writev+0x420/0x5f8
 do_iter_write+0x1b8/0x66c fs/read_write.c:855
 vfs_writev fs/read_write.c:928 [inline]
 do_writev+0x220/0x3ec fs/read_write.c:971
 __do_sys_writev fs/read_write.c:1044 [inline]
 __se_sys_writev fs/read_write.c:1041 [inline]
 __arm64_sys_writev+0x80/0x94 fs/read_write.c:1041
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584
BUG: sleeping function called from invalid context at net/core/sock.c:3282
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 4553, name: syz.1.181
INFO: lockdep is turned off.
Preemption disabled at:
[<ffff800011b34dd0>] spin_lock include/linux/spinlock.h:363 [inline]
[<ffff800011b34dd0>] mptcp_diag_dump_listeners net/mptcp/mptcp_diag.c:95 [inline]
[<ffff800011b34dd0>] mptcp_diag_dump+0x7b0/0x10dc net/mptcp/mptcp_diag.c:194
CPU: 0 PID: 4553 Comm: syz.1.181 Not tainted 5.15.173-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call trace:
 dump_backtrace+0x0/0x530 arch/arm64/kernel/stacktrace.c:152
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:216
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x108/0x170 lib/dump_stack.c:106
 dump_stack+0x1c/0x58 lib/dump_stack.c:113
 ___might_sleep+0x380/0x4dc kernel/sched/core.c:9636
 __might_sleep+0x98/0xf0 kernel/sched/core.c:9590
 __lock_sock_fast+0x3c/0xf0 net/core/sock.c:3282
 lock_sock_fast include/net/sock.h:1712 [inline]
 mptcp_diag_get_info+0x210/0x8a0 net/mptcp/mptcp_diag.c:224
 inet_sk_diag_fill+0xcb8/0x17b4 net/ipv4/inet_diag.c:342
 sk_diag_dump net/mptcp/mptcp_diag.c:24 [inline]
 mptcp_diag_dump_listeners net/mptcp/mptcp_diag.c:122 [inline]
 mptcp_diag_dump+0xb4c/0x10dc net/mptcp/mptcp_diag.c:194
 __inet_diag_dump+0x1e8/0x33c net/ipv4/inet_diag.c:1179
 inet_diag_dump+0x4c/0x5c net/ipv4/inet_diag.c:1198
 netlink_dump+0x4a8/0xad0 net/netlink/af_netlink.c:2280
 __netlink_dump_start+0x474/0x6d4 net/netlink/af_netlink.c:2383
 netlink_dump_start include/linux/netlink.h:258 [inline]
 inet_diag_handler_cmd+0x1a8/0x274 net/ipv4/inet_diag.c:1344
 sock_diag_rcv_msg+0x174/0x39c
 netlink_rcv_skb+0x20c/0x3b8 net/netlink/af_netlink.c:2504
 sock_diag_rcv+0x3c/0x54 net/core/sock_diag.c:276
 netlink_unicast_kernel net/netlink/af_netlink.c:1326 [inline]
 netlink_unicast+0x664/0x938 net/netlink/af_netlink.c:1352
 netlink_sendmsg+0x844/0xb38 net/netlink/af_netlink.c:1920
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 sock_write_iter+0x2b0/0x3f8 net/socket.c:1079
 do_iter_readv_writev+0x420/0x5f8
 do_iter_write+0x1b8/0x66c fs/read_write.c:855
 vfs_writev fs/read_write.c:928 [inline]
 do_writev+0x220/0x3ec fs/read_write.c:971
 __do_sys_writev fs/read_write.c:1044 [inline]
 __se_sys_writev fs/read_write.c:1041 [inline]
 __arm64_sys_writev+0x80/0x94 fs/read_write.c:1041
 __invoke_syscall arch/arm64/kernel/syscall.c:38 [inline]
 invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:52
 el0_svc_common+0x138/0x258 arch/arm64/kernel/syscall.c:142
 do_el0_svc+0x58/0x14c arch/arm64/kernel/syscall.c:181
 el0_svc+0x7c/0x1f0 arch/arm64/kernel/entry-common.c:608
 el0t_64_sync_handler+0x84/0xe4 arch/arm64/kernel/entry-common.c:626
 el0t_64_sync+0x1a0/0x1a4 arch/arm64/kernel/entry.S:584