IPVS: ftp: loaded support on port[0] = 21 ============================================ WARNING: possible recursive locking detected 4.19.211-syzkaller #0 Not tainted -------------------------------------------- syz-executor.3/22992 is trying to acquire lock: 000000005a4d3ab1 (&port_lock_key){-.-.}, at: uart_write+0x1ce/0x6f0 drivers/tty/serial/serial_core.c:591 but task is already holding lock: 000000005a4d3ab1 (&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 6 locks held by syz-executor.3/22992: #0: 000000003191268e (pernet_ops_rwsem){++++}, at: copy_net_ns+0x1d8/0x340 net/core/net_namespace.c:435 #1: 00000000264746b1 (rtnl_mutex){+.+.}, at: register_netdev+0x11/0x50 net/core/dev.c:8857 #2: 0000000031407ded (kernfs_mutex){+.+.}, at: kernfs_add_one+0x51/0x4c0 fs/kernfs/dir.c:769 #3: 000000000f09fa41 (&(&i->lock)->rlock){-.-.}, at: spin_lock include/linux/spinlock.h:329 [inline] #3: 000000000f09fa41 (&(&i->lock)->rlock){-.-.}, at: serial8250_interrupt+0x3a/0x240 drivers/tty/serial/8250/8250_core.c:115 #4: 000000005a4d3ab1 (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1876 #5: 0000000083041994 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:293 stack backtrace: CPU: 1 PID: 22992 Comm: syz-executor.3 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 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:__sanitizer_cov_trace_pc+0x27/0x50 kernel/kcov.c:104 Code: 90 90 90 48 8b 34 24 65 48 8b 04 25 c0 df 01 00 65 8b 15 cc 59 9f 7e 81 e2 00 01 1f 00 75 2b 8b 90 60 13 00 00 83 fa 02 75 20 <48> 8b 88 68 13 00 00 8b 80 64 13 00 00 48 8b 11 48 83 c2 01 48 39 RSP: 0018:ffff88804218f570 EFLAGS: 00000246 ORIG_RAX: ffffffffffffffd5 RAX: ffff8880a8ac6000 RBX: ffff88809b018658 RCX: ffffc90007a35000 RDX: 0000000000000002 RSI: ffffffff81c471f3 RDI: ffff88809b0182f8 RBP: ffff88809b018a08 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000007 R11: 00000000795c0a8e R12: 000000007bd4bde6 R13: dffffc0000000000 R14: ffff88809b0182a0 R15: 0000000000000000 kernfs_name_compare fs/kernfs/dir.c:317 [inline] kernfs_sd_compare fs/kernfs/dir.c:331 [inline] kernfs_link_sibling+0x193/0x410 fs/kernfs/dir.c:358 kernfs_add_one+0x21a/0x4c0 fs/kernfs/dir.c:789 __kernfs_create_file+0x293/0x340 fs/kernfs/file.c:1021 sysfs_add_file_mode_ns+0x226/0x540 fs/sysfs/file.c:307 create_files fs/sysfs/group.c:63 [inline] internal_create_group+0x355/0xb20 fs/sysfs/group.c:147 sysfs_create_group fs/sysfs/group.c:173 [inline] sysfs_create_groups fs/sysfs/group.c:200 [inline] sysfs_create_groups+0x98/0x140 fs/sysfs/group.c:190 device_add_groups drivers/base/core.c:1301 [inline] device_add_attrs drivers/base/core.c:1449 [inline] device_add+0x877/0x16d0 drivers/base/core.c:2139 netdev_register_kobject+0x181/0x430 net/core/net-sysfs.c:1806 register_netdevice+0xb46/0x10f0 net/core/dev.c:8730 register_netdev+0x2d/0x50 net/core/dev.c:8859 sit_init_net+0x37b/0xa10 net/ipv6/sit.c:1865 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 copy_namespaces+0x325/0x3c0 kernel/nsproxy.c:165 copy_process.part.0+0x3a59/0x8260 kernel/fork.c:1916 copy_process kernel/fork.c:1710 [inline] _do_fork+0x22f/0xf30 kernel/fork.c:2219 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x7f0ff9d195a9 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 b8 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007f0ff868c118 EFLAGS: 00000206 ORIG_RAX: 0000000000000038 RAX: ffffffffffffffda RBX: 00007f0ff9e39f80 RCX: 00007f0ff9d195a9 RDX: 00000000200001c0 RSI: 00000000200000c0 RDI: 0000000040000000 RBP: 00007f0ff9d74580 R08: 0000000020000240 R09: 0000000020000240 R10: 0000000020000200 R11: 0000000000000206 R12: 0000000000000000 R13: 00007ffe3226029f R14: 00007f0ff868c300 R15: 0000000000022000 ---------------- Code disassembly (best guess): 0: 90 nop 1: 90 nop 2: 90 nop 3: 48 8b 34 24 mov (%rsp),%rsi 7: 65 48 8b 04 25 c0 df mov %gs:0x1dfc0,%rax e: 01 00 10: 65 8b 15 cc 59 9f 7e mov %gs:0x7e9f59cc(%rip),%edx # 0x7e9f59e3 17: 81 e2 00 01 1f 00 and $0x1f0100,%edx 1d: 75 2b jne 0x4a 1f: 8b 90 60 13 00 00 mov 0x1360(%rax),%edx 25: 83 fa 02 cmp $0x2,%edx 28: 75 20 jne 0x4a * 2a: 48 8b 88 68 13 00 00 mov 0x1368(%rax),%rcx <-- trapping instruction 31: 8b 80 64 13 00 00 mov 0x1364(%rax),%eax 37: 48 8b 11 mov (%rcx),%rdx 3a: 48 83 c2 01 add $0x1,%rdx 3e: 48 rex.W 3f: 39 .byte 0x39