====================================================== WARNING: possible circular locking dependency detected 5.10.45 #1 Not tainted ------------------------------------------------------ syz-executor.3/13930 is trying to acquire lock: ffff88800ca1b578 (&tty->read_wait){....}-{2:2}, at: spin_lock include/linux/spinlock.h:354 [inline] ffff88800ca1b578 (&tty->read_wait){....}-{2:2}, at: io_poll_double_wake+0x1f8/0x550 fs/io_uring.c:5074 but task is already holding lock: ffff88800ca1b528 (&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_restore_fl arch/x86/include/asm/irqflags.h:41 [inline] arch_local_irq_restore arch/x86/include/asm/irqflags.h:84 [inline] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:160 [inline] _raw_spin_unlock_irqrestore+0x25/0x40 kernel/locking/spinlock.c:191 spin_unlock_irqrestore include/linux/spinlock.h:409 [inline] uart_write+0x304/0x580 drivers/tty/serial/serial_core.c:615 do_output_char+0x5e4/0x860 drivers/tty/n_tty.c:442 process_output drivers/tty/n_tty.c:509 [inline] n_tty_write+0x487/0xf90 drivers/tty/n_tty.c:2361 do_tty_write drivers/tty/tty_io.c:1028 [inline] file_tty_write.constprop.0+0x4f8/0x8d0 drivers/tty/tty_io.c:1118 redirected_tty_write+0xa1/0xc0 drivers/tty/tty_io.c:1125 call_write_iter include/linux/fs.h:1903 [inline] do_iter_readv_writev+0x476/0x750 fs/read_write.c:740 do_iter_write+0x18d/0x670 fs/read_write.c:866 vfs_writev+0x1aa/0x5d0 fs/read_write.c:939 do_writev+0x139/0x300 fs/read_write.c:982 do_syscall_64+0x33/0x40 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #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.3/13930: #0: ffff88800ca1b1c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_lock+0xbd/0x120 drivers/tty/tty_mutex.c:19 #1: ffff88800ca1b528 (&tty->write_wait){-.-.}-{2:2}, at: __wake_up_common_lock+0xb4/0x130 kernel/sched/wait.c:122 stack backtrace: CPU: 1 PID: 13930 Comm: syz-executor.3 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:00007f482cd0f188 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: 00007ffcb919442f R14: 00007f482cd0f300 R15: 0000000000022000 9p: Unknown uid 18446744073709551615 9p: Unknown uid 18446744073709551615 9p: Unknown uid 18446744073709551615