REISERFS (device loop2): Created .reiserfs_priv - reserved for xattr storage. UDF-fs: INFO Mounting volume 'LinuxUDF', timestamp 2022/11/22 14:59 (1000) IPVS: ftp: loaded support on port[0] = 21 overlayfs: missing 'lowerdir' ============================================ WARNING: possible recursive locking detected 4.19.211-syzkaller #0 Not tainted -------------------------------------------- syz-executor.4/22134 is trying to acquire lock: 00000000f719ad08 (&port_lock_key){-.-.}, at: uart_write+0x1ce/0x6f0 drivers/tty/serial/serial_core.c:591 but task is already holding lock: 00000000f719ad08 (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1876 other info that might help us debug this: Possible unsafe locking scenario: CPU0 ---- lock(&port_lock_key); lock(&port_lock_key); *** DEADLOCK *** May be due to missing lock nesting notation 5 locks held by syz-executor.4/22134: #0: 0000000096b510cd (pernet_ops_rwsem){++++}, at: copy_net_ns+0x1d8/0x340 net/core/net_namespace.c:435 #1: 0000000028ce57d2 (rtnl_mutex){+.+.}, at: ip_tunnel_init_net+0x321/0x990 net/ipv4/ip_tunnel.c:1034 #2: 00000000a561f68d (&(&i->lock)->rlock){-.-.}, at: spin_lock include/linux/spinlock.h:329 [inline] #2: 00000000a561f68d (&(&i->lock)->rlock){-.-.}, at: serial8250_interrupt+0x3a/0x240 drivers/tty/serial/8250/8250_core.c:115 #3: 00000000f719ad08 (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1876 #4: 000000007b81bf7e (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:293 stack backtrace: CPU: 1 PID: 22134 Comm: syz-executor.4 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/12/2023 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1fc/0x2ef lib/dump_stack.c:118 print_deadlock_bug kernel/locking/lockdep.c:1764 [inline] check_deadlock kernel/locking/lockdep.c:1808 [inline] validate_chain kernel/locking/lockdep.c:2404 [inline] __lock_acquire.cold+0x121/0x57e kernel/locking/lockdep.c:3416 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:152 uart_write+0x1ce/0x6f0 drivers/tty/serial/serial_core.c:591 n_hdlc_send_frames+0x278/0x470 drivers/tty/n_hdlc.c:403 n_hdlc_tty_wakeup+0xa0/0xc0 drivers/tty/n_hdlc.c:479 tty_wakeup+0xd4/0x110 drivers/tty/tty_io.c:534 tty_port_default_wakeup+0x26/0x40 drivers/tty/tty_port.c:50 serial8250_tx_chars+0x490/0xaf0 drivers/tty/serial/8250/8250_port.c:1813 serial8250_handle_irq.part.0+0x31f/0x3d0 drivers/tty/serial/8250/8250_port.c:1900 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1873 [inline] serial8250_default_handle_irq+0xae/0x220 drivers/tty/serial/8250/8250_port.c:1916 serial8250_interrupt+0x101/0x240 drivers/tty/serial/8250/8250_core.c:125 __handle_irq_event_percpu+0x27e/0x8e0 kernel/irq/handle.c:149 handle_irq_event_percpu kernel/irq/handle.c:189 [inline] handle_irq_event+0x102/0x290 kernel/irq/handle.c:206 handle_edge_irq+0x260/0xcf0 kernel/irq/chip.c:800 generic_handle_irq_desc include/linux/irqdesc.h:155 [inline] handle_irq+0x35/0x50 arch/x86/kernel/irq_64.c:87 do_IRQ+0x93/0x1c0 arch/x86/kernel/irq.c:246 common_interrupt+0xf/0xf arch/x86/entry/entry_64.S:670 RIP: 0010:arch_local_irq_restore arch/x86/include/asm/paravirt.h:789 [inline] RIP: 0010:__raw_read_unlock_irqrestore include/linux/rwlock_api_smp.h:235 [inline] RIP: 0010:_raw_read_unlock_irqrestore+0xa3/0xe0 kernel/locking/spinlock.c:256 Code: 48 c7 c0 88 82 f1 89 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 2f 48 83 3d 5c 2b d8 01 00 74 15 48 89 df 57 9d <0f> 1f 44 00 00 eb b2 e8 db e5 e6 f8 eb c0 0f 0b 0f 0b 48 c7 c7 88 RSP: 0018:ffff888090ebf920 EFLAGS: 00000286 ORIG_RAX: ffffffffffffffd5 RAX: 1ffffffff13e3051 RBX: 0000000000000286 RCX: 1ffff11011981d1a RDX: dffffc0000000000 RSI: ffff88808cc0e8b0 RDI: 0000000000000286 RBP: ffffffff8ae7ac20 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001 R13: ffff88809f253680 R14: 0000000000000000 R15: ffff88809f253680 netlink_lock_table net/netlink/af_netlink.c:470 [inline] netlink_broadcast_filtered+0x9c/0xbc0 net/netlink/af_netlink.c:1522 netlink_broadcast net/netlink/af_netlink.c:1549 [inline] nlmsg_multicast include/net/netlink.h:591 [inline] nlmsg_notify+0x15e/0x1f0 net/netlink/af_netlink.c:2506 rtnl_notify net/core/rtnetlink.c:736 [inline] rtmsg_ifinfo_send net/core/rtnetlink.c:3377 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:3392 [inline] rtmsg_ifinfo_event net/core/rtnetlink.c:3380 [inline] rtmsg_ifinfo+0xf0/0x120 net/core/rtnetlink.c:3398 register_netdevice+0xed5/0x10f0 net/core/dev.c:8782 __ip_tunnel_create+0x398/0x580 net/ipv4/ip_tunnel.c:280 ip_tunnel_init_net+0x330/0x990 net/ipv4/ip_tunnel.c:1035 ops_init+0xb3/0x410 net/core/net_namespace.c:129 setup_net+0x2c2/0x720 net/core/net_namespace.c:316 copy_net_ns+0x1f7/0x340 net/core/net_namespace.c:439 create_new_namespaces+0x3f6/0x7b0 kernel/nsproxy.c:107 unshare_nsproxy_namespaces+0xbd/0x1f0 kernel/nsproxy.c:206 ksys_unshare+0x36c/0x9a0 kernel/fork.c:2542 __do_sys_unshare kernel/fork.c:2610 [inline] __se_sys_unshare kernel/fork.c:2608 [inline] __x64_sys_unshare+0x2d/0x40 kernel/fork.c:2608 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f1b0ccb60c9 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 00 00 90 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:00007f1b0b228168 EFLAGS: 00000246 ORIG_RAX: 0000000000000110 RAX: ffffffffffffffda RBX: 00007f1b0cdd5f80 RCX: 00007f1b0ccb60c9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000040000000 RBP: 00007f1b0cd11ae9 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007ffc10514f2f R14: 00007f1b0b228300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 48 c7 c0 88 82 f1 89 mov $0xffffffff89f18288,%rax 7: 48 ba 00 00 00 00 00 movabs $0xdffffc0000000000,%rdx e: fc ff df 11: 48 c1 e8 03 shr $0x3,%rax 15: 80 3c 10 00 cmpb $0x0,(%rax,%rdx,1) 19: 75 2f jne 0x4a 1b: 48 83 3d 5c 2b d8 01 cmpq $0x0,0x1d82b5c(%rip) # 0x1d82b7f 22: 00 23: 74 15 je 0x3a 25: 48 89 df mov %rbx,%rdi 28: 57 push %rdi 29: 9d popfq * 2a: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) <-- trapping instruction 2f: eb b2 jmp 0xffffffe3 31: e8 db e5 e6 f8 callq 0xf8e6e611 36: eb c0 jmp 0xfffffff8 38: 0f 0b ud2 3a: 0f 0b ud2 3c: 48 rex.W 3d: c7 .byte 0xc7 3e: c7 (bad) 3f: 88 .byte 0x88