EXT4-fs (loop0): Unrecognized mount option "com{it=0x0000000000000002" or missing value
======================================================
WARNING: possible circular locking dependency detected
5.10.49 #1 Not tainted
------------------------------------------------------
syz-executor.6/21955 is trying to acquire lock:
ffff888058fd1578 (&tty->read_wait){....}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline]
ffff888058fd1578 (&tty->read_wait){....}-{2:2}, at: io_poll_double_wake+0x1f8/0x550 fs/io_uring.c:5074

but task is already holding lock:
ffff888058fd1528 (&tty->write_wait){-.-.}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&tty->write_wait){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x36/0x50 kernel/locking/spinlock.c:159
       __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122
       tty_port_default_wakeup+0x26/0x40 drivers/tty/tty_port.c:50
       serial8250_tx_chars+0x516/0xb40 drivers/tty/serial/8250/8250_port.c:1844
       serial8250_handle_irq.part.0+0x3f1/0x4c0 drivers/tty/serial/8250/8250_port.c:1931
EXT4-fs (loop0): Unrecognized mount option "com{it=0x0000000000000002" or missing value
       serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1904 [inline]
       serial8250_default_handle_irq+0xb8/0x230 drivers/tty/serial/8250/8250_port.c:1947
       serial8250_interrupt+0xf4/0x1a0 drivers/tty/serial/8250/8250_core.c:126
       __handle_irq_event_percpu+0x2ef/0x810 kernel/irq/handle.c:156
       handle_irq_event_percpu kernel/irq/handle.c:196 [inline]
       handle_irq_event+0x102/0x290 kernel/irq/handle.c:213
       handle_edge_irq+0x249/0xd00 kernel/irq/chip.c:819
       asm_call_irq_on_stack+0x12/0x20
       __run_irq_on_irqstack arch/x86/include/asm/irq_stack.h:48 [inline]
       run_irq_on_irqstack_cond arch/x86/include/asm/irq_stack.h:101 [inline]
       handle_irq arch/x86/kernel/irq.c:230 [inline]
       __common_interrupt arch/x86/kernel/irq.c:249 [inline]
       common_interrupt+0xe6/0x190 arch/x86/kernel/irq.c:239
       asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:635
       native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline]
       arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline]
       default_idle+0xe/0x10 arch/x86/kernel/process.c:688
       default_idle_call+0x87/0xd0 kernel/sched/idle.c:112
       cpuidle_idle_call kernel/sched/idle.c:194 [inline]
       do_idle+0x3a9/0x520 kernel/sched/idle.c:300
       cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:396
       secondary_startup_64_no_verify+0xc2/0xcb

-> #3 (&port_lock_key){-.-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x36/0x50 kernel/locking/spinlock.c:159
       serial8250_console_write+0x87a/0xa90 drivers/tty/serial/8250/8250_port.c:3304
       call_console_drivers kernel/printk/printk.c:1909 [inline]
       console_unlock+0x826/0xb30 kernel/printk/printk.c:2523
       register_console kernel/printk/printk.c:2864 [inline]
       register_console+0x53d/0x800 kernel/printk/printk.c:2754
       univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:690
       console_init+0x361/0x4fa kernel/printk/printk.c:2974
       start_kernel+0x2f9/0x4a2 init/main.c:988
       secondary_startup_64_no_verify+0xc2/0xcb

-> #2 (console_owner){-.-.}-{0:0}:
       console_lock_spinning_enable kernel/printk/printk.c:1761 [inline]
       console_unlock+0x360/0xb30 kernel/printk/printk.c:2520
       vprintk_emit+0x1da/0x4d0 kernel/printk/printk.c:2052
       vprintk_func+0x8b/0x140 kernel/printk/printk_safe.c:401
       printk+0xba/0xed kernel/printk/printk.c:2100
       fail_dump lib/fault-inject.c:45 [inline]
       should_fail+0x472/0x5a0 lib/fault-inject.c:146
       should_failslab+0x5/0x10 mm/slab_common.c:1193
       slab_pre_alloc_hook mm/slab.h:516 [inline]
       slab_alloc_node mm/slub.c:2814 [inline]
       slab_alloc mm/slub.c:2897 [inline]
       kmem_cache_alloc+0x5b/0x350 mm/slub.c:2902
       __sigqueue_alloc+0x23f/0x550 kernel/signal.c:435
       __send_signal+0x5db/0x1030 kernel/signal.c:1116
       do_send_sig_info kernel/signal.c:1291 [inline]
       send_sig_info kernel/signal.c:1606 [inline]
       send_sig+0xcb/0x160 kernel/signal.c:1616
       sk_stream_error+0xaa/0x100 net/core/stream.c:188
       tcp_sendmsg_locked+0x193e/0x2ec0 net/ipv4/tcp.c:1429
       tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1444
       inet6_sendmsg+0xb5/0x140 net/ipv6/af_inet6.c:638
       sock_sendmsg_nosec net/socket.c:651 [inline]
       sock_sendmsg+0xee/0x190 net/socket.c:671
       ____sys_sendmsg+0x709/0x870 net/socket.c:2340
       ___sys_sendmsg+0xf3/0x170 net/socket.c:2394
       __sys_sendmsg+0xe5/0x1b0 net/socket.c:2427
       do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #1 (&sighand->siglock){..-.}-{2:2}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x36/0x50 kernel/locking/spinlock.c:159
       __lock_task_sighand+0x108/0x2e0 kernel/signal.c:1391
       lock_task_sighand include/linux/sched/signal.h:688 [inline]
       task_work_add+0x1db/0x2b0 kernel/task_work.c:58
       io_req_task_work_add fs/io_uring.c:2048 [inline]
       __io_async_wake+0x443/0x8d0 fs/io_uring.c:4961
       __wake_up_common+0x14c/0x4c0 kernel/sched/wait.c:93
       __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:123
       tty_ldisc_lock+0x40/0xb0 drivers/tty/tty_ldisc.c:335
       tty_ldisc_hangup+0x204/0x690 drivers/tty/tty_ldisc.c:744
       __tty_hangup.part.0+0x50d/0x9b0 drivers/tty/tty_io.c:624
       __tty_hangup drivers/tty/tty_io.c:574 [inline]
       tty_vhangup drivers/tty/tty_io.c:697 [inline]
       tty_ioctl+0x103e/0x17c0 drivers/tty/tty_io.c:2683
       vfs_ioctl fs/ioctl.c:48 [inline]
       __do_sys_ioctl fs/ioctl.c:753 [inline]
       __se_sys_ioctl fs/ioctl.c:739 [inline]
       __x64_sys_ioctl+0x196/0x210 fs/ioctl.c:739
       do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

-> #0 (&tty->read_wait){....}-{2:2}:
       check_prev_add kernel/locking/lockdep.c:2871 [inline]
       check_prevs_add kernel/locking/lockdep.c:2996 [inline]
       validate_chain kernel/locking/lockdep.c:3611 [inline]
       __lock_acquire+0x2a48/0x5a80 kernel/locking/lockdep.c:4836
       lock_acquire kernel/locking/lockdep.c:5446 [inline]
       lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5411
       __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
       _raw_spin_lock+0x27/0x40 kernel/locking/spinlock.c:151
       spin_lock include/linux/spinlock.h:354 [inline]
       io_poll_double_wake+0x1f8/0x550 fs/io_uring.c:5074
       __wake_up_common+0x14c/0x4c0 kernel/sched/wait.c:93
       __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:123
       tty_ldisc_lock+0x55/0xb0 drivers/tty/tty_ldisc.c:336
       tty_ldisc_hangup+0x204/0x690 drivers/tty/tty_ldisc.c:744
       __tty_hangup.part.0+0x50d/0x9b0 drivers/tty/tty_io.c:624
       __tty_hangup drivers/tty/tty_io.c:574 [inline]
       tty_vhangup drivers/tty/tty_io.c:697 [inline]
       tty_ioctl+0x103e/0x17c0 drivers/tty/tty_io.c:2683
       vfs_ioctl fs/ioctl.c:48 [inline]
       __do_sys_ioctl fs/ioctl.c:753 [inline]
       __se_sys_ioctl fs/ioctl.c:739 [inline]
       __x64_sys_ioctl+0x196/0x210 fs/ioctl.c:739
       do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
       entry_SYSCALL_64_after_hwframe+0x44/0xa9

other info that might help us debug this:

Chain exists of:
  &tty->read_wait --> &port_lock_key --> &tty->write_wait

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&tty->write_wait);
                               lock(&port_lock_key);
                               lock(&tty->write_wait);
  lock(&tty->read_wait);

 *** DEADLOCK ***

2 locks held by syz-executor.6/21955:
 #0: ffff888058fd11c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_lock+0xbd/0x120 drivers/tty/tty_mutex.c:19
 #1: ffff888058fd1528 (&tty->write_wait){-.-.}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122

stack backtrace:
CPU: 1 PID: 21955 Comm: syz-executor.6 Not tainted 5.10.49 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x107/0x163 lib/dump_stack.c:118
 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2120
 check_prev_add kernel/locking/lockdep.c:2871 [inline]
 check_prevs_add kernel/locking/lockdep.c:2996 [inline]
 validate_chain kernel/locking/lockdep.c:3611 [inline]
 __lock_acquire+0x2a48/0x5a80 kernel/locking/lockdep.c:4836
 lock_acquire kernel/locking/lockdep.c:5446 [inline]
 lock_acquire+0x197/0x490 kernel/locking/lockdep.c:5411
 __raw_spin_lock include/linux/spinlock_api_smp.h:142 [inline]
 _raw_spin_lock+0x27/0x40 kernel/locking/spinlock.c:151
 spin_lock include/linux/spinlock.h:354 [inline]
 io_poll_double_wake+0x1f8/0x550 fs/io_uring.c:5074
 __wake_up_common+0x14c/0x4c0 kernel/sched/wait.c:93
 __wake_up_common_lock+0xd0/0x130 kernel/sched/wait.c:123
 tty_ldisc_lock+0x55/0xb0 drivers/tty/tty_ldisc.c:336
 tty_ldisc_hangup+0x204/0x690 drivers/tty/tty_ldisc.c:744
 __tty_hangup.part.0+0x50d/0x9b0 drivers/tty/tty_io.c:624
 __tty_hangup drivers/tty/tty_io.c:574 [inline]
 tty_vhangup drivers/tty/tty_io.c:697 [inline]
 tty_ioctl+0x103e/0x17c0 drivers/tty/tty_io.c:2683
 vfs_ioctl fs/ioctl.c:48 [inline]
 __do_sys_ioctl fs/ioctl.c:753 [inline]
 __se_sys_ioctl fs/ioctl.c:739 [inline]
 __x64_sys_ioctl+0x196/0x210 fs/ioctl.c:739
 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
audit: type=1326 audit(1626229785.406:119): auid=0 uid=0 gid=0 ses=4 subj=system_u:system_r:kernel_t:s0 pid=21966 comm="syz-executor.3" exe="/syz-executor.3" sig=9 arch=c000003e syscall=231 compat=0 ip=0x466609 code=0x0
RIP: 0033:0x466609
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 bc ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f6341d07188 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 0000000000466609
RDX: 0000000000000000 RSI: 0000000000005437 RDI: 0000000000000004
RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
R13: 00007ffc6d20df0f R14: 00007f6341d07300 R15: 0000000000022000
audit: type=1326 audit(1626229786.225:120): auid=0 uid=0 gid=0 ses=4 subj=system_u:system_r:kernel_t:s0 pid=21966 comm="syz-executor.3" exe="/syz-executor.3" sig=9 arch=c000003e syscall=231 compat=0 ip=0x466609 code=0x0