======================================================
WARNING: possible circular locking dependency detected
5.10.45 #1 Not tainted
------------------------------------------------------
syz-executor.5/10828 is trying to acquire lock:
ffff88800b9b2578 (&tty->read_wait){....}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline]
ffff88800b9b2578 (&tty->read_wait){....}-{2:2}, at: io_poll_double_wake+0x1f8/0x550 fs/io_uring.c:5074

but task is already holding lock:
ffff88800b9b2528 (&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
       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:1194
       slab_pre_alloc_hook mm/slab.h:516 [inline]
       slab_alloc_node mm/slub.c:2813 [inline]
       slab_alloc mm/slub.c:2896 [inline]
       kmem_cache_alloc+0x5b/0x350 mm/slub.c:2901
       __sigqueue_alloc+0x23f/0x550 kernel/signal.c:435
       __send_signal+0x5db/0x1030 kernel/signal.c:1116
       force_sig_info_to_task+0x2a0/0x3a0 kernel/signal.c:1334
       force_sig_fault_to_task kernel/signal.c:1673 [inline]
       force_sig_fault+0xb0/0xf0 kernel/signal.c:1680
       __bad_area_nosemaphore+0x270/0x320 arch/x86/mm/fault.c:832
       do_user_addr_fault+0x89c/0xc30 arch/x86/mm/fault.c:1342
       handle_page_fault arch/x86/mm/fault.c:1436 [inline]
       exc_page_fault+0xa2/0x1a0 arch/x86/mm/fault.c:1492
       asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:580

-> #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:2869 [inline]
       check_prevs_add kernel/locking/lockdep.c:2994 [inline]
       validate_chain kernel/locking/lockdep.c:3609 [inline]
       __lock_acquire+0x2a48/0x5a80 kernel/locking/lockdep.c:4834
       lock_acquire kernel/locking/lockdep.c:5444 [inline]
       lock_acquire+0x197/0x6c0 kernel/locking/lockdep.c:5409
       __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.5/10828:
 #0: ffff88800b9b21c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_lock+0xbd/0x120 drivers/tty/tty_mutex.c:19
 #1: ffff88800b9b2528 (&tty->write_wait){-.-.}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122

stack backtrace:
CPU: 0 PID: 10828 Comm: syz-executor.5 Not tainted 5.10.45 #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:2118
 check_prev_add kernel/locking/lockdep.c:2869 [inline]
 check_prevs_add kernel/locking/lockdep.c:2994 [inline]
 validate_chain kernel/locking/lockdep.c:3609 [inline]
 __lock_acquire+0x2a48/0x5a80 kernel/locking/lockdep.c:4834
 lock_acquire kernel/locking/lockdep.c:5444 [inline]
 lock_acquire+0x197/0x6c0 kernel/locking/lockdep.c:5409
 __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
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:00007f4849cd6188 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: 00007ffc897af8bf R14: 00007f4849cd6300 R15: 0000000000022000
hpet: Lost 5 RTC interrupts
FAULT_INJECTION: forcing a failure.
name fail_usercopy, interval 1, probability 0, space 0, times 0
CPU: 0 PID: 10859 Comm: syz-executor.7 Not tainted 5.10.45 #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
 fail_dump lib/fault-inject.c:52 [inline]
 should_fail.cold+0x5/0xa lib/fault-inject.c:146
 __copy_to_user include/linux/uaccess.h:144 [inline]
 save_xstate_epilog arch/x86/kernel/fpu/signal.c:95 [inline]
 copy_fpstate_to_sigframe+0x869/0xa80 arch/x86/kernel/fpu/signal.c:208
 get_sigframe arch/x86/kernel/signal.c:274 [inline]
 __setup_rt_frame arch/x86/kernel/signal.c:450 [inline]
 setup_rt_frame arch/x86/kernel/signal.c:702 [inline]
 handle_signal arch/x86/kernel/signal.c:746 [inline]
 arch_do_signal+0xf8a/0x1a90 arch/x86/kernel/signal.c:791
 exit_to_user_mode_loop kernel/entry/common.c:161 [inline]
 exit_to_user_mode_prepare+0xf7/0x160 kernel/entry/common.c:191
 irqentry_exit_to_user_mode+0x5/0x30 kernel/entry/common.c:279
 exc_page_fault+0xca/0x1a0 arch/x86/mm/fault.c:1495
 asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:580
RIP: 0033:0x40584d
Code: 8b 81 0c 01 00 00 44 8b 89 08 01 00 00 48 8b 54 24 d8 c1 e0 04 8d b8 7f 01 00 00 83 e7 c0 45 85 c9 74 07 89 d0 31 d2 41 f7 f1 <f3> 41 0f 6f 00 89 d0 c1 e0 06 48 01 c6 0f 11 06 f3 41 0f 6f 48 10
RSP: 002b:00007fe159f30178 EFLAGS: 00010246
RAX: 0000000000000000 RBX: 000000000056bf80 RCX: 0000000020ffa000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000140
RBP: 00007fe159f301d0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
R13: 00007ffcd547ae9f R14: 00007fe159f30300 R15: 0000000000022000