====================================================== WARNING: possible circular locking dependency detected 5.10.0-rc7-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor150/12886 is trying to acquire lock: ffffffff8b2487e0 (console_owner){-...}-{0:0}, at: console_unlock+0x2fb/0xbb0 kernel/printk/printk.c:2474 but task is already holding lock: ffffffff8fb072f8 (&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 asm_call_irq_on_stack+0xf/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+0x120/0x200 arch/x86/kernel/irq.c:239 asm_common_interrupt+0x1e/0x40 arch/x86/include/asm/idtentry.h:622 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+0x3fa/0x590 kernel/sched/idle.c:299 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:395 start_secondary+0x266/0x340 arch/x86/kernel/smpboot.c:266 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+0x880/0xa90 drivers/tty/serial/8250/8250_port.c:3292 call_console_drivers kernel/printk/printk.c:1885 [inline] console_unlock+0x841/0xbb0 kernel/printk/printk.c:2499 vprintk_emit+0x1a1/0x4c0 kernel/printk/printk.c:2028 vprintk_func+0x8d/0x1e0 kernel/printk/printk_safe.c:393 printk+0xba/0xed kernel/printk/printk.c:2076 register_console kernel/printk/printk.c:2850 [inline] register_console+0x5d1/0x800 kernel/printk/printk.c:2730 univ8250_console_init+0x3a/0x46 drivers/tty/serial/8250/8250_core.c:690 console_init+0x3c7/0x596 kernel/printk/printk.c:2950 start_kernel+0x2fc/0x491 init/main.c:988 secondary_startup_64_no_verify+0xb0/0xbb -> #0 (console_owner){-...}-{0:0}: check_prev_add kernel/locking/lockdep.c:2868 [inline] check_prevs_add kernel/locking/lockdep.c:2993 [inline] validate_chain kernel/locking/lockdep.c:3608 [inline] __lock_acquire+0x2ade/0x5500 kernel/locking/lockdep.c:4832 lock_acquire kernel/locking/lockdep.c:5437 [inline] lock_acquire+0x29d/0x740 kernel/locking/lockdep.c:5402 console_lock_spinning_enable kernel/printk/printk.c:1737 [inline] console_unlock+0x37a/0xbb0 kernel/printk/printk.c:2496 vprintk_emit+0x1a1/0x4c0 kernel/printk/printk.c:2028 vprintk_func+0x8d/0x1e0 kernel/printk/printk_safe.c:393 printk+0xba/0xed kernel/printk/printk.c:2076 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:1681 __fput+0x285/0x920 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:151 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0xb64/0x29b0 kernel/exit.c:809 do_group_exit+0x125/0x310 kernel/exit.c:906 __do_sys_exit_group kernel/exit.c:917 [inline] __se_sys_exit_group kernel/exit.c:915 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:915 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 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-executor150/12886: #0: ffff8880181861c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_lock+0xbd/0x120 drivers/tty/tty_mutex.c:19 #1: ffffffff8fb072f8 (&port->lock){-.-.}-{2:2}, at: tty_port_close_start.part.0+0x28/0x550 drivers/tty/tty_port.c:567 #2: ffffffff8b328b60 (console_lock){+.+.}-{0:0}, at: vprintk_func+0x8d/0x1e0 kernel/printk/printk_safe.c:393 stack backtrace: CPU: 1 PID: 12886 Comm: syz-executor150 Not tainted 5.10.0-rc7-syzkaller #0 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.12.0-59-gc9ba5276e321-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:2117 check_prev_add kernel/locking/lockdep.c:2868 [inline] check_prevs_add kernel/locking/lockdep.c:2993 [inline] validate_chain kernel/locking/lockdep.c:3608 [inline] __lock_acquire+0x2ade/0x5500 kernel/locking/lockdep.c:4832 lock_acquire kernel/locking/lockdep.c:5437 [inline] lock_acquire+0x29d/0x740 kernel/locking/lockdep.c:5402 console_lock_spinning_enable kernel/printk/printk.c:1737 [inline] console_unlock+0x37a/0xbb0 kernel/printk/printk.c:2496 vprintk_emit+0x1a1/0x4c0 kernel/printk/printk.c:2028 vprintk_func+0x8d/0x1e0 kernel/printk/printk_safe.c:393 printk+0xba/0xed kernel/printk/printk.c:2076 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:1681 __fput+0x285/0x920 fs/file_table.c:281 task_work_run+0xdd/0x190 kernel/task_work.c:151 exit_task_work include/linux/task_work.h:30 [inline] do_exit+0xb64/0x29b0 kernel/exit.c:809 do_group_exit+0x125/0x310 kernel/exit.c:906 __do_sys_exit_group kernel/exit.c:917 [inline] __se_sys_exit_group kernel/exit.c:915 [inline] __x64_sys_exit_group+0x3a/0x50 kernel/exit.c:915 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x438fe8 Code: Unable to access opcode bytes at RIP 0x438fbe. RSP: 002b:00007ffeb87b3a68 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 0000000000438fe8 RDX: 0000000000000000 RSI: 000000000000003c RDI: 0000000000000000 RBP: 00000000004b4cb0 R08: 00000000000000e7 R09: ffffffffffffffd4 R10: 00007ffeb87b3b00 R11: 0000000000000246 R12: 0000000000000001 R13: 00000000006c8320 R14: 0000000000400f80 R15: 00007ffeb87b3ad8