------------[ cut here ]------------ refcount_t: addition on 0; use-after-free. WARNING: CPU: 1 PID: 21130 at lib/refcount.c:25 refcount_warn_saturate+0x132/0x1a0 lib/refcount.c:25 Modules linked in: CPU: 1 PID: 21130 Comm: syz-executor.5 Not tainted 6.1.68-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023 RIP: 0010:refcount_warn_saturate+0x132/0x1a0 lib/refcount.c:25 Code: 0a 01 48 c7 c7 20 bb 3c 8b e8 2a ed 1a fd 0f 0b eb a9 e8 e1 00 53 fd c6 05 9d b8 27 0a 01 48 c7 c7 80 bb 3c 8b e8 0e ed 1a fd <0f> 0b eb 8d e8 c5 00 53 fd c6 05 82 b8 27 0a 01 48 c7 c7 e0 bb 3c RSP: 0018:ffffc9000ce5fa88 EFLAGS: 00010246 RAX: 4e8eeb0c897ef900 RBX: 0000000000000002 RCX: ffff888012758000 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000002 R08: ffffffff81527dae R09: fffff520019cbeb1 R10: 0000000000000000 R11: dffffc0000000001 R12: dffffc0000000000 R13: ffff88807aa0e000 R14: ffff88814b273fc0 R15: ffff8880284b81e0 FS: 0000555555a04480(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000001b32f28000 CR3: 000000002859d000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __refcount_inc include/linux/refcount.h:250 [inline] refcount_inc include/linux/refcount.h:267 [inline] sock_hold include/net/sock.h:773 [inline] inet_csk_listen_stop+0x88b/0xae0 net/ipv4/inet_connection_sock.c:1391 mptcp_check_listen_stop+0x19d/0x2a0 net/mptcp/protocol.c:3010 __mptcp_close+0xaf/0x960 net/mptcp/protocol.c:3024 mptcp_close+0x26/0x120 net/mptcp/protocol.c:3089 inet_release+0x174/0x1f0 net/ipv4/af_inet.c:429 __sock_release net/socket.c:652 [inline] sock_close+0xcd/0x230 net/socket.c:1387 __fput+0x3b7/0x890 fs/file_table.c:320 task_work_run+0x246/0x300 kernel/task_work.c:179 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:171 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:204 __syscall_exit_to_user_mode_work kernel/entry/common.c:286 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:297 do_syscall_64+0x49/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7fd1c287ba9a Code: 48 3d 00 f0 ff ff 77 48 c3 0f 1f 80 00 00 00 00 48 83 ec 18 89 7c 24 0c e8 03 7f 02 00 8b 7c 24 0c 89 c2 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 36 89 d7 89 44 24 0c e8 63 7f 02 00 8b 44 24 RSP: 002b:00007ffd801c3c30 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00007fd1c287ba9a RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 00007fd1c299d980 R08: 0000001b33520000 R09: 000000000000018d R10: 00000000818e5f6a R11: 0000000000000293 R12: 0000000000152133 R13: ffffffffffffffff R14: 00007fd1c2400000 R15: 0000000000151df2