syzbot

======================================================
WARNING: possible circular locking dependency detected
5.15.175-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor342/4162 is trying to acquire lock:
ffff88802a8b8120 (sk_lock-AF_INET6){+.+.}-{0:0}, at: inet_sk_diag_fill+0xf6a/0x1cb0 net/ipv4/inet_diag.c:342

but task is already holding lock:
ffffc900018751a8 (&h->lhash2[i].lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
ffffc900018751a8 (&h->lhash2[i].lock){+.+.}-{2:2}, at: mptcp_diag_dump_listeners net/mptcp/mptcp_diag.c:95 [inline]
ffffc900018751a8 (&h->lhash2[i].lock){+.+.}-{2:2}, at: mptcp_diag_dump+0x869/0x1330 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}:
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154
       spin_lock include/linux/spinlock.h:363 [inline]
       __inet_hash+0xe4/0x8e0 net/ipv4/inet_hashtables.c:613
       inet_csk_listen_start+0x231/0x310 net/ipv4/inet_connection_sock.c:1115
       inet_listen+0x2c9/0x7c0 net/ipv4/af_inet.c:231
       __sys_listen+0x1a7/0x220 net/socket.c:1754
       __do_sys_listen net/socket.c:1763 [inline]
       __se_sys_listen net/socket.c:1761 [inline]
       __x64_sys_listen+0x56/0x60 net/socket.c:1761
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

-> #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+0x1649/0x5930 kernel/locking/lockdep.c:3788
       __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
       lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
       lock_sock_fast include/net/sock.h:1710 [inline]
       mptcp_diag_get_info+0x276/0xa10 net/mptcp/mptcp_diag.c:224
       inet_sk_diag_fill+0xf6a/0x1cb0 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+0xd1d/0x1330 net/mptcp/mptcp_diag.c:194
       __inet_diag_dump+0x20e/0x3a0 net/ipv4/inet_diag.c:1179
       netlink_dump+0x5a4/0xca0 net/netlink/af_netlink.c:2265
       __netlink_dump_start+0x50f/0x6d0 net/netlink/af_netlink.c:2368
       netlink_dump_start include/linux/netlink.h:258 [inline]
       inet_diag_handler_cmd+0x1d7/0x2a0 net/ipv4/inet_diag.c:1344
       sock_diag_rcv_msg+0xd5/0x400
       netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2489
       sock_diag_rcv+0x26/0x40 net/core/sock_diag.c:276
       netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
       netlink_unicast+0x7b6/0x980 net/netlink/af_netlink.c:1337
       netlink_sendmsg+0xa30/0xd60 net/netlink/af_netlink.c:1905
       sock_sendmsg_nosec net/socket.c:704 [inline]
       __sock_sendmsg net/socket.c:716 [inline]
       sock_write_iter+0x39b/0x530 net/socket.c:1079
       do_iter_readv_writev+0x594/0x7a0
       do_iter_write+0x1e6/0x760 fs/read_write.c:855
       vfs_writev fs/read_write.c:928 [inline]
       do_writev+0x281/0x470 fs/read_write.c:971
       do_syscall_x64 arch/x86/entry/common.c:50 [inline]
       do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
       entry_SYSCALL_64_after_hwframe+0x66/0xd0

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-executor342/4162:
 #0: ffffffff8dc4b748 (sock_diag_mutex){+.+.}-{3:3}, at: sock_diag_rcv+0x17/0x40 net/core/sock_diag.c:275
 #1: ffffffff8dc4b5a8 (sock_diag_table_mutex){+.+.}-{3:3}, at: __sock_diag_cmd net/core/sock_diag.c:229 [inline]
 #1: ffffffff8dc4b5a8 (sock_diag_table_mutex){+.+.}-{3:3}, at: sock_diag_rcv_msg+0x206/0x400 net/core/sock_diag.c:265
 #2: ffff88814c582690 (nlk_cb_mutex-SOCK_DIAG){+.+.}-{3:3}, at: __netlink_dump_start+0x12e/0x6d0 net/netlink/af_netlink.c:2334
 #3: ffffffff8dd27f28 (inet_diag_table_mutex){+.+.}-{3:3}, at: inet_diag_lock_handler net/ipv4/inet_diag.c:63 [inline]
 #3: ffffffff8dd27f28 (inet_diag_table_mutex){+.+.}-{3:3}, at: __inet_diag_dump+0x191/0x3a0 net/ipv4/inet_diag.c:1177
 #4: ffffffff8cb1fd20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x5/0x30 include/linux/rcupdate.h:311
 #5: ffffc900018751a8 (&h->lhash2[i].lock){+.+.}-{2:2}, at: spin_lock include/linux/spinlock.h:363 [inline]
 #5: ffffc900018751a8 (&h->lhash2[i].lock){+.+.}-{2:2}, at: mptcp_diag_dump_listeners net/mptcp/mptcp_diag.c:95 [inline]
 #5: ffffc900018751a8 (&h->lhash2[i].lock){+.+.}-{2:2}, at: mptcp_diag_dump+0x869/0x1330 net/mptcp/mptcp_diag.c:194

stack backtrace:
CPU: 1 PID: 4162 Comm: syz-executor342 Not tainted 5.15.175-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 check_noncircular+0x2f8/0x3b0 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+0x1649/0x5930 kernel/locking/lockdep.c:3788
 __lock_acquire+0x1295/0x1ff0 kernel/locking/lockdep.c:5012
 lock_acquire+0x1db/0x4f0 kernel/locking/lockdep.c:5623
 lock_sock_fast include/net/sock.h:1710 [inline]
 mptcp_diag_get_info+0x276/0xa10 net/mptcp/mptcp_diag.c:224
 inet_sk_diag_fill+0xf6a/0x1cb0 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+0xd1d/0x1330 net/mptcp/mptcp_diag.c:194
 __inet_diag_dump+0x20e/0x3a0 net/ipv4/inet_diag.c:1179
 netlink_dump+0x5a4/0xca0 net/netlink/af_netlink.c:2265
 __netlink_dump_start+0x50f/0x6d0 net/netlink/af_netlink.c:2368
 netlink_dump_start include/linux/netlink.h:258 [inline]
 inet_diag_handler_cmd+0x1d7/0x2a0 net/ipv4/inet_diag.c:1344
 sock_diag_rcv_msg+0xd5/0x400
 netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2489
 sock_diag_rcv+0x26/0x40 net/core/sock_diag.c:276
 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
 netlink_unicast+0x7b6/0x980 net/netlink/af_netlink.c:1337
 netlink_sendmsg+0xa30/0xd60 net/netlink/af_netlink.c:1905
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 sock_write_iter+0x39b/0x530 net/socket.c:1079
 do_iter_readv_writev+0x594/0x7a0
 do_iter_write+0x1e6/0x760 fs/read_write.c:855
 vfs_writev fs/read_write.c:928 [inline]
 do_writev+0x281/0x470 fs/read_write.c:971
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc28fe06429
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc7bf910d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007ffc7bf912a8 RCX: 00007fc28fe06429
RDX: 0000000000000001 RSI: 0000000020000280 RDI: 0000000000000004
RBP: 00007fc28fe79610 R08: 00007ffc7bf912a8 R09: 00007ffc7bf912a8
R10: 00007ffc7bf912a8 R11: 0000000000000246 R12: 0000000000000001
R13: 00007ffc7bf91298 R14: 0000000000000001 R15: 0000000000000001
 </TASK>
BUG: sleeping function called from invalid context at net/core/sock.c:3282
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 4162, name: syz-executor342
INFO: lockdep is turned off.
Preemption disabled at:
[<0000000000000000>] 0x0
CPU: 1 PID: 4162 Comm: syz-executor342 Not tainted 5.15.175-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/13/2024
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0x1e3/0x2d0 lib/dump_stack.c:106
 ___might_sleep+0x547/0x6a0 kernel/sched/core.c:9636
 __lock_sock_fast+0x2f/0xe0 net/core/sock.c:3282
 lock_sock_fast include/net/sock.h:1712 [inline]
 mptcp_diag_get_info+0x282/0xa10 net/mptcp/mptcp_diag.c:224
 inet_sk_diag_fill+0xf6a/0x1cb0 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+0xd1d/0x1330 net/mptcp/mptcp_diag.c:194
 __inet_diag_dump+0x20e/0x3a0 net/ipv4/inet_diag.c:1179
 netlink_dump+0x5a4/0xca0 net/netlink/af_netlink.c:2265
 __netlink_dump_start+0x50f/0x6d0 net/netlink/af_netlink.c:2368
 netlink_dump_start include/linux/netlink.h:258 [inline]
 inet_diag_handler_cmd+0x1d7/0x2a0 net/ipv4/inet_diag.c:1344
 sock_diag_rcv_msg+0xd5/0x400
 netlink_rcv_skb+0x1cf/0x410 net/netlink/af_netlink.c:2489
 sock_diag_rcv+0x26/0x40 net/core/sock_diag.c:276
 netlink_unicast_kernel net/netlink/af_netlink.c:1311 [inline]
 netlink_unicast+0x7b6/0x980 net/netlink/af_netlink.c:1337
 netlink_sendmsg+0xa30/0xd60 net/netlink/af_netlink.c:1905
 sock_sendmsg_nosec net/socket.c:704 [inline]
 __sock_sendmsg net/socket.c:716 [inline]
 sock_write_iter+0x39b/0x530 net/socket.c:1079
 do_iter_readv_writev+0x594/0x7a0
 do_iter_write+0x1e6/0x760 fs/read_write.c:855
 vfs_writev fs/read_write.c:928 [inline]
 do_writev+0x281/0x470 fs/read_write.c:971
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x66/0xd0
RIP: 0033:0x7fc28fe06429
Code: 48 83 c4 28 c3 e8 37 17 00 00 0f 1f 80 00 00 00 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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffc7bf910d8 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007ffc7bf912a8 RCX: 00007fc28fe06429