EXT4-fs (loop1): mounting with "discard" option, but the device does not support discard EXT4-fs (loop1): mounted filesystem without journal. Opts: ,errors=continue ============================================ WARNING: possible recursive locking detected 4.19.211-syzkaller #0 Not tainted -------------------------------------------- kworker/u4:0/7 is trying to acquire lock: 00000000c837e5cb (&port_lock_key){-.-.}, at: uart_write+0x1ce/0x6f0 drivers/tty/serial/serial_core.c:591 but task is already holding lock: 00000000c837e5cb (&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 block nbd0: Attempted send on invalid socket 5 locks held by kworker/u4:0/7: #0: 00000000bae3408f ((wq_completion)"%s""bat_events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2124 #1: 00000000cce90ea9 ((work_completion)(&(&bat_priv->nc.work)->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2128 #2: 00000000aa324689 (&(&i->lock)->rlock){-.-.}, at: spin_lock include/linux/spinlock.h:329 [inline] #2: 00000000aa324689 (&(&i->lock)->rlock){-.-.}, at: serial8250_interrupt+0x3a/0x240 drivers/tty/serial/8250/8250_core.c:115 #3: 00000000c837e5cb (&port_lock_key){-.-.}, at: serial8250_handle_irq.part.0+0x21/0x3d0 drivers/tty/serial/8250/8250_port.c:1876 #4: 00000000c81a969d (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:293 stack backtrace: CPU: 1 PID: 7 Comm: kworker/u4:0 Not tainted 4.19.211-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022 Workqueue: bat_events batadv_nc_worker 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:__local_bh_disable_ip+0xce/0x190 kernel/softirq.c:130 Code: ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 a2 00 00 00 48 83 3d 25 69 b8 08 00 0f 84 81 00 00 00 48 89 ef 57 9d <0f> 1f 44 00 00 65 8b 05 d6 c5 c8 7e 25 ff ff ff 7f 39 d8 74 0f 5b RSP: 0018:ffff8880b5a47c10 EFLAGS: 00000286 ORIG_RAX: ffffffffffffffd2 RAX: 1ffffffff13e3051 RBX: 0000000000000201 RCX: 0000000000000001 RDX: dffffc0000000000 RSI: 0000000000000201 RDI: 0000000000000286 RBP: 0000000000000286 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000004 R11: 0000000000000000 R12: ffffffff87d8badc R13: ffffffff87d8da80 R14: 0000000000000017 R15: ffff888094e8a6c0 __raw_spin_lock_bh include/linux/spinlock_api_smp.h:134 [inline] _raw_spin_lock_bh+0x13/0x40 kernel/locking/spinlock.c:168 spin_lock_bh include/linux/spinlock.h:334 [inline] batadv_nc_purge_paths+0xdc/0x310 net/batman-adv/network-coding.c:453 batadv_nc_worker+0x6fa/0xd50 net/batman-adv/network-coding.c:731 process_one_work+0x864/0x1570 kernel/workqueue.c:2153 worker_thread+0x64c/0x1130 kernel/workqueue.c:2296 kthread+0x33f/0x460 kernel/kthread.c:259 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415 ---------------- Code disassembly (best guess): 0: ba 00 00 00 00 mov $0x0,%edx 5: 00 fc add %bh,%ah 7: ff (bad) 8: df 48 c1 fisttps -0x3f(%rax) b: e8 03 80 3c 10 callq 0x103c8013 10: 00 0f add %cl,(%rdi) 12: 85 a2 00 00 00 48 test %esp,0x48000000(%rdx) 18: 83 3d 25 69 b8 08 00 cmpl $0x0,0x8b86925(%rip) # 0x8b86944 1f: 0f 84 81 00 00 00 je 0xa6 25: 48 89 ef mov %rbp,%rdi 28: 57 push %rdi 29: 9d popfq * 2a: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) <-- trapping instruction 2f: 65 8b 05 d6 c5 c8 7e mov %gs:0x7ec8c5d6(%rip),%eax # 0x7ec8c60c 36: 25 ff ff ff 7f and $0x7fffffff,%eax 3b: 39 d8 cmp %ebx,%eax 3d: 74 0f je 0x4e 3f: 5b pop %rbx