====================================================== WARNING: possible circular locking dependency detected 5.11.0-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor077/6408 is trying to acquire lock: ffffffff8a679a20 (console_owner){....}-{0:0}, at: console_unlock+0x242/0x8d0 kernel/printk/printk.c:2545 but task is already holding lock: ffff8880277d7158 (&port->lock){-.-.}-{2:2}, at: pty_write+0xc8/0x1b0 drivers/tty/pty.c:120 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+0x1a/0xb0 drivers/tty/tty_port.c:288 tty_port_default_wakeup+0x6/0x30 drivers/tty/tty_port.c:47 serial8250_tx_chars+0x3ac/0x890 drivers/tty/serial/8250/8250_port.c:1832 serial8250_handle_irq.part.0+0x21f/0x2b0 drivers/tty/serial/8250/8250_port.c:1919 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1892 [inline] serial8250_default_handle_irq+0x79/0x1d0 drivers/tty/serial/8250/8250_port.c:1935 serial8250_interrupt+0xd1/0x1a0 drivers/tty/serial/8250/8250_core.c:126 __handle_irq_event_percpu+0x256/0x680 kernel/irq/handle.c:156 handle_irq_event_percpu kernel/irq/handle.c:196 [inline] handle_irq_event+0xfa/0x260 kernel/irq/handle.c:213 handle_edge_irq+0x203/0xb50 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:620 native_safe_halt arch/x86/include/asm/irqflags.h:60 [inline] arch_safe_halt arch/x86/include/asm/irqflags.h:103 [inline] acpi_safe_halt drivers/acpi/processor_idle.c:110 [inline] acpi_idle_do_entry+0x161/0x1c0 drivers/acpi/processor_idle.c:516 acpi_idle_enter+0x2c0/0x4b0 drivers/acpi/processor_idle.c:647 cpuidle_enter_state+0x152/0xb40 drivers/cpuidle/cpuidle.c:237 cpuidle_enter+0x45/0xa0 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:299 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:396 start_kernel+0x333/0x351 init/main.c:1061 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+0x6e9/0x8d0 drivers/tty/serial/8250/8250_port.c:3292 call_console_drivers kernel/printk/printk.c:1856 [inline] console_unlock+0x61c/0x8d0 kernel/printk/printk.c:2570 vprintk_emit+0xf8/0x2d0 kernel/printk/printk.c:2092 printk+0xad/0xde kernel/printk/printk.c:2140 register_console kernel/printk/printk.c:2921 [inline] register_console+0x40d/0x620 kernel/printk/printk.c:2801 univ8250_console_init+0x1f/0x22 drivers/tty/serial/8250/8250_core.c:690 console_init+0x271/0x38c kernel/printk/printk.c:3021 start_kernel+0x26b/0x351 init/main.c:989 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+0x2b3b/0x57d0 kernel/locking/lockdep.c:4832 lock_acquire kernel/locking/lockdep.c:5442 [inline] lock_acquire+0x1a8/0x720 kernel/locking/lockdep.c:5407 console_lock_spinning_enable kernel/printk/printk.c:1708 [inline] console_unlock+0x2b7/0x8d0 kernel/printk/printk.c:2567 vprintk_emit+0xf8/0x2d0 kernel/printk/printk.c:2092 printk+0xad/0xde kernel/printk/printk.c:2140 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:1195 slab_pre_alloc_hook mm/slab.h:495 [inline] slab_alloc_node mm/slub.c:2817 [inline] slab_alloc mm/slub.c:2900 [inline] __kmalloc+0x72/0x3e0 mm/slub.c:3981 kmalloc include/linux/slab.h:557 [inline] tty_buffer_alloc+0x205/0x270 drivers/tty/tty_buffer.c:175 __tty_buffer_request_room+0x112/0x260 drivers/tty/tty_buffer.c:273 tty_insert_flip_string_fixed_flag+0x78/0x1e0 drivers/tty/tty_buffer.c:318 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0xfa/0x1b0 drivers/tty/pty.c:122 tty_put_char+0xfe/0x120 drivers/tty/tty_io.c:3056 __process_echoes+0x3ee/0x7c0 drivers/tty/n_tty.c:729 flush_echoes drivers/tty/n_tty.c:830 [inline] __receive_buf drivers/tty/n_tty.c:1649 [inline] n_tty_receive_buf_common+0x88a/0x28e0 drivers/tty/n_tty.c:1744 tiocsti drivers/tty/tty_io.c:2211 [inline] tty_ioctl+0x81a/0x1340 drivers/tty/tty_io.c:2591 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+0x11f/0x190 fs/ioctl.c:739 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 *** 5 locks held by syz-executor077/6408: #0: ffff888022fbb098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x1f/0x70 drivers/tty/tty_ldisc.c:266 #1: ffff888022fbb2e8 (&o_tty->termios_rwsem/1){++++}-{3:3}, at: n_tty_receive_signal_char+0x17/0x110 drivers/tty/n_tty.c:1244 #2: ffffc900035e3378 (&ldata->output_lock){+.+.}-{3:3}, at: flush_echoes drivers/tty/n_tty.c:828 [inline] #2: ffffc900035e3378 (&ldata->output_lock){+.+.}-{3:3}, at: __receive_buf drivers/tty/n_tty.c:1649 [inline] #2: ffffc900035e3378 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_receive_buf_common+0x842/0x28e0 drivers/tty/n_tty.c:1744 #3: ffff8880277d7158 (&port->lock){-.-.}-{2:2}, at: pty_write+0xc8/0x1b0 drivers/tty/pty.c:120 #4: ffffffff8a759da0 (console_lock){+.+.}-{0:0}, at: printk+0xad/0xde kernel/printk/printk.c:2140 stack backtrace: CPU: 0 PID: 6408 Comm: syz-executor077 Not tainted 5.11.0-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+0x9a/0xcc lib/dump_stack.c:120 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+0x2b3b/0x57d0 kernel/locking/lockdep.c:4832 lock_acquire kernel/locking/lockdep.c:5442 [inline] lock_acquire+0x1a8/0x720 kernel/locking/lockdep.c:5407 console_lock_spinning_enable kernel/printk/printk.c:1708 [inline] console_unlock+0x2b7/0x8d0 kernel/printk/printk.c:2567 vprintk_emit+0xf8/0x2d0 kernel/printk/printk.c:2092 printk+0xad/0xde kernel/printk/printk.c:2140 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:1195 slab_pre_alloc_hook mm/slab.h:495 [inline] slab_alloc_node mm/slub.c:2817 [inline] slab_alloc mm/slub.c:2900 [inline] __kmalloc+0x72/0x3e0 mm/slub.c:3981 kmalloc include/linux/slab.h:557 [inline] tty_buffer_alloc+0x205/0x270 drivers/tty/tty_buffer.c:175 __tty_buffer_request_room+0x112/0x260 drivers/tty/tty_buffer.c:273 tty_insert_flip_string_fixed_flag+0x78/0x1e0 drivers/tty/tty_buffer.c:318 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0xfa/0x1b0 drivers/tty/pty.c:122 tty_put_char+0xfe/0x120 drivers/tty/tty_io.c:3056 __process_echoes+0x3ee/0x7c0 drivers/tty/n_tty.c:729 flush_echoes drivers/tty/n_tty.c:830 [inline] __receive_buf drivers/tty/n_tty.c:1649 [inline] n_tty_receive_buf_common+0x88a/0x28e0 drivers/tty/n_tty.c:1744 tiocsti drivers/tty/tty_io.c:2211 [inline] tty_ioctl+0x81a/0x1340 drivers/tty/tty_io.c:2591 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+0x11f/0x190 fs/ioctl.c:739 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7efd988f5189 Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 b1 14 00 00 90 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 c0 ff ff ff f7 d8 64 89 01 48 RSP: 002b:00007ffd821a4dc8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 00007efd988f5189 RDX: 0000000020000000 RSI: 0000000000005412 RDI: 0000000000000004 RBP: 00007ffd821a4de0 R08: 0000000000000001 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000005 R13: 431bde82d7b634db R14: 0000000000000000 R15: 0000000000000000