RDX: 0000000020000100 RSI: 0000000000005412 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f42021136d4 R13: 00000000004c62a7 R14: 00000000004dd8f0 R15: 0000000000000006 ====================================================== WARNING: possible circular locking dependency detected 4.14.164-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.5/32214 is trying to acquire lock: (console_owner){-.-.}, at: [] console_trylock_spinning kernel/printk/printk.c:1658 [inline] (console_owner){-.-.}, at: [] vprintk_emit kernel/printk/printk.c:1922 [inline] (console_owner){-.-.}, at: [] vprintk_emit+0x2f1/0x600 kernel/printk/printk.c:1888 but task is already holding lock: (&(&port->lock)->rlock){-.-.}, at: [] pty_write+0xe0/0x1d0 drivers/tty/pty.c:120 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&(&port->lock)->rlock){-.-.}: lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:160 tty_port_tty_get+0x22/0x90 drivers/tty/tty_port.c:287 tty_port_default_wakeup+0x16/0x40 drivers/tty/tty_port.c:46 tty_port_tty_wakeup+0x57/0x70 drivers/tty/tty_port.c:389 uart_write_wakeup+0x46/0x70 drivers/tty/serial/serial_core.c:116 serial8250_tx_chars+0x40d/0xa10 drivers/tty/serial/8250/8250_port.c:1810 serial8250_handle_irq.part.0+0x206/0x250 drivers/tty/serial/8250/8250_port.c:1883 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1869 [inline] serial8250_default_handle_irq+0xa1/0x120 drivers/tty/serial/8250/8250_port.c:1899 serial8250_interrupt+0xe9/0x1a0 drivers/tty/serial/8250/8250_core.c:129 __handle_irq_event_percpu+0x125/0x7f0 kernel/irq/handle.c:147 handle_irq_event_percpu+0x65/0x130 kernel/irq/handle.c:187 handle_irq_event+0xa7/0x134 kernel/irq/handle.c:204 handle_edge_irq+0x22b/0x840 kernel/irq/chip.c:770 generic_handle_irq_desc include/linux/irqdesc.h:159 [inline] handle_irq+0x39/0x50 arch/x86/kernel/irq_64.c:87 do_IRQ+0x99/0x1d0 arch/x86/kernel/irq.c:230 ret_from_intr+0x0/0x1e native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60 arch_cpu_idle+0xa/0x10 arch/x86/kernel/process.c:557 default_idle_call+0x36/0x90 kernel/sched/idle.c:98 cpuidle_idle_call kernel/sched/idle.c:156 [inline] do_idle+0x262/0x3d0 kernel/sched/idle.c:246 cpu_startup_entry+0x1b/0x20 kernel/sched/idle.c:351 rest_init+0x1d9/0x1e2 init/main.c:434 start_kernel+0x6df/0x6fd init/main.c:708 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:399 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:380 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240 -> #1 (&port_lock_key){-.-.}: lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x95/0xcd kernel/locking/spinlock.c:160 serial8250_console_write+0x709/0x930 drivers/tty/serial/8250/8250_port.c:3232 univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:597 call_console_drivers kernel/printk/printk.c:1725 [inline] console_unlock+0x9ba/0xed0 kernel/printk/printk.c:2397 vprintk_emit kernel/printk/printk.c:1923 [inline] vprintk_emit+0x1f9/0x600 kernel/printk/printk.c:1888 vprintk_default+0x28/0x30 kernel/printk/printk.c:1963 vprintk_func+0x5d/0x159 kernel/printk/printk_safe.c:401 printk+0x9e/0xbc kernel/printk/printk.c:1996 register_console+0x614/0x9e0 kernel/printk/printk.c:2716 univ8250_console_init+0x33/0x3f drivers/tty/serial/8250/8250_core.c:692 console_init+0x4d/0x5d kernel/printk/printk.c:2797 start_kernel+0x43c/0x6fd init/main.c:634 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:399 x86_64_start_kernel+0x77/0x7b arch/x86/kernel/head64.c:380 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240 -> #0 (console_owner){-.-.}: check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487 lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 console_trylock_spinning kernel/printk/printk.c:1679 [inline] vprintk_emit kernel/printk/printk.c:1922 [inline] vprintk_emit+0x32e/0x600 kernel/printk/printk.c:1888 vprintk_default+0x28/0x30 kernel/printk/printk.c:1963 vprintk_func+0x5d/0x159 kernel/printk/printk_safe.c:401 printk+0x9e/0xbc kernel/printk/printk.c:1996 fail_dump lib/fault-inject.c:44 [inline] should_fail.cold+0xe4/0x159 lib/fault-inject.c:149 should_failslab+0xdb/0x130 mm/failslab.c:32 slab_pre_alloc_hook mm/slab.h:421 [inline] slab_alloc mm/slab.c:3376 [inline] __do_kmalloc mm/slab.c:3718 [inline] __kmalloc+0x71/0x7a0 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:169 [inline] __tty_buffer_request_room+0x1a4/0x500 drivers/tty/tty_buffer.c:267 tty_insert_flip_string_fixed_flag+0x8a/0x1c0 drivers/tty/tty_buffer.c:312 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x113/0x1d0 drivers/tty/pty.c:122 tty_put_char+0x108/0x130 drivers/tty/tty_io.c:2880 __process_echoes+0x4a1/0x8a0 drivers/tty/n_tty.c:729 flush_echoes drivers/tty/n_tty.c:829 [inline] __receive_buf drivers/tty/n_tty.c:1648 [inline] n_tty_receive_buf_common+0x8ed/0x2570 drivers/tty/n_tty.c:1742 n_tty_receive_buf+0x31/0x3b drivers/tty/n_tty.c:1771 tiocsti drivers/tty/tty_io.c:2186 [inline] tty_ioctl+0xded/0x1320 drivers/tty/tty_io.c:2572 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 other info that might help us debug this: Chain exists of: console_owner --> &port_lock_key --> &(&port->lock)->rlock Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&(&port->lock)->rlock); lock(&port_lock_key); lock(&(&port->lock)->rlock); lock(console_owner); *** DEADLOCK *** 4 locks held by syz-executor.5/32214: #0: (&tty->ldisc_sem){++++}, at: [] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:376 #1: (&o_tty->termios_rwsem/1){++++}, at: [] n_tty_receive_buf_common+0x8f/0x2570 drivers/tty/n_tty.c:1705 #2: (&ldata->output_lock){+.+.}, at: [] flush_echoes drivers/tty/n_tty.c:827 [inline] #2: (&ldata->output_lock){+.+.}, at: [] __receive_buf drivers/tty/n_tty.c:1648 [inline] #2: (&ldata->output_lock){+.+.}, at: [] n_tty_receive_buf_common+0x8ad/0x2570 drivers/tty/n_tty.c:1742 #3: (&(&port->lock)->rlock){-.-.}, at: [] pty_write+0xe0/0x1d0 drivers/tty/pty.c:120 stack backtrace: CPU: 1 PID: 32214 Comm: syz-executor.5 Not tainted 4.14.164-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x142/0x197 lib/dump_stack.c:58 print_circular_bug.isra.0.cold+0x1cc/0x28f kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1901 [inline] check_prevs_add kernel/locking/lockdep.c:2018 [inline] validate_chain kernel/locking/lockdep.c:2460 [inline] __lock_acquire+0x2cb3/0x4620 kernel/locking/lockdep.c:3487 lock_acquire+0x16f/0x430 kernel/locking/lockdep.c:3994 console_trylock_spinning kernel/printk/printk.c:1679 [inline] vprintk_emit kernel/printk/printk.c:1922 [inline] vprintk_emit+0x32e/0x600 kernel/printk/printk.c:1888 vprintk_default+0x28/0x30 kernel/printk/printk.c:1963 vprintk_func+0x5d/0x159 kernel/printk/printk_safe.c:401 printk+0x9e/0xbc kernel/printk/printk.c:1996 fail_dump lib/fault-inject.c:44 [inline] should_fail.cold+0xe4/0x159 lib/fault-inject.c:149 should_failslab+0xdb/0x130 mm/failslab.c:32 slab_pre_alloc_hook mm/slab.h:421 [inline] slab_alloc mm/slab.c:3376 [inline] __do_kmalloc mm/slab.c:3718 [inline] __kmalloc+0x71/0x7a0 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:169 [inline] __tty_buffer_request_room+0x1a4/0x500 drivers/tty/tty_buffer.c:267 tty_insert_flip_string_fixed_flag+0x8a/0x1c0 drivers/tty/tty_buffer.c:312 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x113/0x1d0 drivers/tty/pty.c:122 tty_put_char+0x108/0x130 drivers/tty/tty_io.c:2880 __process_echoes+0x4a1/0x8a0 drivers/tty/n_tty.c:729 flush_echoes drivers/tty/n_tty.c:829 [inline] __receive_buf drivers/tty/n_tty.c:1648 [inline] n_tty_receive_buf_common+0x8ed/0x2570 drivers/tty/n_tty.c:1742 n_tty_receive_buf+0x31/0x3b drivers/tty/n_tty.c:1771 tiocsti drivers/tty/tty_io.c:2186 [inline] tty_ioctl+0xded/0x1320 drivers/tty/tty_io.c:2572 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:500 [inline] do_vfs_ioctl+0x7ae/0x1060 fs/ioctl.c:684 SYSC_ioctl fs/ioctl.c:701 [inline] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692 do_syscall_64+0x1e8/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x45af49 RSP: 002b:00007f4202112c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f4202112c90 RCX: 000000000045af49 RDX: 0000000020000100 RSI: 0000000000005412 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f42021136d4 R13: 00000000004c62a7 R14: 00000000004dd8f0 R15: 0000000000000006 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 audit: type=1400 audit(1578953109.302:124): avc: denied { dac_override } for pid=32609 comm="syz-executor.4" capability=1 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=cap_userns permissive=1 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 device bridge_slave_1 left promiscuous mode bridge0: port 2(bridge_slave_1) entered disabled state ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 device bridge_slave_0 left promiscuous mode bridge0: port 1(bridge_slave_0) entered disabled state ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 device veth1_vlan left promiscuous mode device veth0_vlan left promiscuous mode ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 device hsr_slave_1 left promiscuous mode device hsr_slave_0 left promiscuous mode team0 (unregistering): Port device team_slave_1 removed team0 (unregistering): Port device team_slave_0 removed bond0 (unregistering): Releasing backup interface bond_slave_1 bond0 (unregistering): Releasing backup interface bond_slave_0 bond0 (unregistering): Released all slaves ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0 ubi: mtd0 is already attached to ubi0