====================================================== WARNING: possible circular locking dependency detected 5.12.0-rc5-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor148/9901 is trying to acquire lock: ffffffff8be83060 (console_owner){....}-{0:0}, at: console_unlock+0x2f2/0xc80 kernel/printk/printk.c:2551 but task is already holding lock: ffffffff90104d38 (&port->lock){-.-.}-{2:2}, at: tty_port_close_start.part.0+0x28/0x550 drivers/tty/tty_port.c:567 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&port->lock){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:159 tty_port_tty_get+0x1f/0x100 drivers/tty/tty_port.c:288 tty_port_default_wakeup+0x11/0x40 drivers/tty/tty_port.c:47 serial8250_tx_chars+0x487/0xa80 drivers/tty/serial/8250/8250_port.c:1832 serial8250_handle_irq.part.0+0x328/0x3d0 drivers/tty/serial/8250/8250_port.c:1919 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1892 [inline] serial8250_default_handle_irq+0xb2/0x220 drivers/tty/serial/8250/8250_port.c:1935 serial8250_interrupt+0xfd/0x200 drivers/tty/serial/8250/8250_core.c:126 __handle_irq_event_percpu+0x303/0x8f0 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+0x25f/0xd00 kernel/irq/chip.c:819 generic_handle_irq_desc include/linux/irqdesc.h:158 [inline] handle_irq arch/x86/kernel/irq.c:231 [inline] __common_interrupt+0x9e/0x200 arch/x86/kernel/irq.c:250 common_interrupt+0x9f/0xd0 arch/x86/kernel/irq.c:240 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:623 native_safe_halt arch/x86/include/asm/irqflags.h:51 [inline] arch_safe_halt arch/x86/include/asm/irqflags.h:89 [inline] acpi_safe_halt drivers/acpi/processor_idle.c:111 [inline] acpi_idle_do_entry+0x1c9/0x250 drivers/acpi/processor_idle.c:517 acpi_idle_enter+0x361/0x500 drivers/acpi/processor_idle.c:654 cpuidle_enter_state+0x1b1/0xc80 drivers/cpuidle/cpuidle.c:237 cpuidle_enter+0x4a/0xa0 drivers/cpuidle/cpuidle.c:351 call_cpuidle kernel/sched/idle.c:158 [inline] cpuidle_idle_call kernel/sched/idle.c:239 [inline] do_idle+0x3e1/0x590 kernel/sched/idle.c:300 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:397 start_kernel+0x475/0x496 init/main.c:1064 secondary_startup_64_no_verify+0xb0/0xbb -> #1 (&port_lock_key){-.-.}-{2:2}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x39/0x50 kernel/locking/spinlock.c:159 serial8250_console_write+0x8b2/0xae0 drivers/tty/serial/8250/8250_port.c:3292 call_console_drivers kernel/printk/printk.c:1862 [inline] console_unlock+0x895/0xc80 kernel/printk/printk.c:2576 vprintk_emit+0x1ca/0x560 kernel/printk/printk.c:2098 vprintk_func+0x8d/0x1e0 kernel/printk/printk_safe.c:401 printk+0xba/0xed kernel/printk/printk.c:2146 register_console kernel/printk/printk.c:2927 [inline] register_console+0x606/0x840 kernel/printk/printk.c:2807 univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:690 console_init+0x3c7/0x596 kernel/printk/printk.c:3027 start_kernel+0x306/0x496 init/main.c:993 secondary_startup_64_no_verify+0xb0/0xbb -> #0 (console_owner){....}-{0:0}: check_prev_add kernel/locking/lockdep.c:2936 [inline] check_prevs_add kernel/locking/lockdep.c:3059 [inline] validate_chain kernel/locking/lockdep.c:3674 [inline] __lock_acquire+0x2b14/0x54c0 kernel/locking/lockdep.c:4900 lock_acquire kernel/locking/lockdep.c:5510 [inline] lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5475 console_lock_spinning_enable kernel/printk/printk.c:1714 [inline] console_unlock+0x371/0xc80 kernel/printk/printk.c:2573 vprintk_emit+0x1ca/0x560 kernel/printk/printk.c:2098 vprintk_func+0x8d/0x1e0 kernel/printk/printk_safe.c:401 printk+0xba/0xed kernel/printk/printk.c:2146 tty_port_close_start.part.0+0x503/0x550 drivers/tty/tty_port.c:569 tty_port_close_start drivers/tty/tty_port.c:641 [inline] tty_port_close+0x46/0x170 drivers/tty/tty_port.c:634 tty_release+0x45e/0x1210 drivers/tty/tty_io.c:1779 __fput+0x288/0x920 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:140 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:208 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Chain exists of: console_owner --> &port_lock_key --> &port->lock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&port->lock); lock(&port_lock_key); lock(&port->lock); lock(console_owner); *** DEADLOCK *** 3 locks held by syz-executor148/9901: #0: ffff88801354d1c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_lock+0xbd/0x120 drivers/tty/tty_mutex.c:19 #1: ffffffff90104d38 (&port->lock){-.-.}-{2:2}, at: tty_port_close_start.part.0+0x28/0x550 drivers/tty/tty_port.c:567 #2: ffffffff8bf633e0 (console_lock){+.+.}-{0:0}, at: vprintk_func+0x8d/0x1e0 kernel/printk/printk_safe.c:401 stack backtrace: CPU: 0 PID: 9901 Comm: syz-executor148 Not tainted 5.12.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline] dump_stack+0x141/0x1d7 lib/dump_stack.c:120 check_noncircular+0x25f/0x2e0 kernel/locking/lockdep.c:2127 check_prev_add kernel/locking/lockdep.c:2936 [inline] check_prevs_add kernel/locking/lockdep.c:3059 [inline] validate_chain kernel/locking/lockdep.c:3674 [inline] __lock_acquire+0x2b14/0x54c0 kernel/locking/lockdep.c:4900 lock_acquire kernel/locking/lockdep.c:5510 [inline] lock_acquire+0x1ab/0x740 kernel/locking/lockdep.c:5475 console_lock_spinning_enable kernel/printk/printk.c:1714 [inline] console_unlock+0x371/0xc80 kernel/printk/printk.c:2573 vprintk_emit+0x1ca/0x560 kernel/printk/printk.c:2098 vprintk_func+0x8d/0x1e0 kernel/printk/printk_safe.c:401 printk+0xba/0xed kernel/printk/printk.c:2146 tty_port_close_start.part.0+0x503/0x550 drivers/tty/tty_port.c:569 tty_port_close_start drivers/tty/tty_port.c:641 [inline] tty_port_close+0x46/0x170 drivers/tty/tty_port.c:634 tty_release+0x45e/0x1210 drivers/tty/tty_io.c:1779 __fput+0x288/0x920 fs/file_table.c:280 task_work_run+0xdd/0x1a0 kernel/task_work.c:140 tracehook_notify_resume include/linux/tracehook.h:189 [inline] exit_to_user_mode_loop kernel/entry/common.c:174 [inline] exit_to_user_mode_prepare+0x249/0x250 kernel/entry/common.c:208 __syscall_exit_to_user_mode_work kernel/entry/common.c:290 [inline] syscall_exit_to_user_mode+0x19/0x60 kernel/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x40b2cb Code: 0f 05 48 3d 00 f0 ff ff 77 45 c3 0f 1f 40 00 48 83 ec 18 89 7c 24 0c e8 63 fc ff ff 8b 7c 24 0c 41 89 c0 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 35 44 89 c7 89 44 24 0c e8 a1 fc ff ff 8b 44 RSP: 002b:00007ffcb6f97050 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000004 RCX: 000000000040b2cb RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000032 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000293 R12: 00000000004d727c R13: 00007ffcb6f970a0 R14: 00007ffcb6f970c0 R15: 0000000000403d80