FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 ttyprintk ttyprintk: tty_port_close_start: tty->count = 1 port count = 3 CPU: 0 PID: 10844 Comm: syz-executor.2 Not tainted 4.14.166-syzkaller #0 ====================================================== WARNING: possible circular locking dependency detected 4.14.166-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.0/10814 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: [] tty_port_close_start.part.0+0x2b/0x4e0 drivers/tty/tty_port.c:572 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 tty_port_close_start.part.0+0x491/0x4e0 drivers/tty/tty_port.c:574 tty_port_close_start drivers/tty/tty_port.c:646 [inline] tty_port_close+0x41/0xc0 drivers/tty/tty_port.c:639 tpk_close+0x7a/0x8c drivers/char/ttyprintk.c:109 tty_release+0x373/0xd60 drivers/tty/tty_io.c:1670 __fput+0x275/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x114/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297 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 *** 2 locks held by syz-executor.0/10814: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x68/0x80 drivers/tty/tty_mutex.c:19 #1: (&(&port->lock)->rlock){-.-.}, at: [] tty_port_close_start.part.0+0x2b/0x4e0 drivers/tty/tty_port.c:572 stack backtrace: CPU: 1 PID: 10814 Comm: syz-executor.0 Not tainted 4.14.166-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 tty_port_close_start.part.0+0x491/0x4e0 drivers/tty/tty_port.c:574 tty_port_close_start drivers/tty/tty_port.c:646 [inline] tty_port_close+0x41/0xc0 drivers/tty/tty_port.c:639 tpk_close+0x7a/0x8c drivers/char/ttyprintk.c:109 tty_release+0x373/0xd60 drivers/tty/tty_io.c:1670 __fput+0x275/0x7a0 fs/file_table.c:210 ____fput+0x16/0x20 fs/file_table.c:244 task_work_run+0x114/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1da/0x220 arch/x86/entry/common.c:164 prepare_exit_to_usermode arch/x86/entry/common.c:199 [inline] syscall_return_slowpath arch/x86/entry/common.c:270 [inline] do_syscall_64+0x4bc/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x414ee1 RSP: 002b:00007ffd8d090520 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000013 RCX: 0000000000414ee1 RDX: 0000000000000000 RSI: 00000000000018f7 RDI: 0000000000000012 RBP: 0000000000000001 R08: 00000000159418f7 R09: 00000000159418fb R10: 00007ffd8d090600 R11: 0000000000000293 R12: 000000000075c9a0 R13: 000000000075c9a0 R14: 0000000000762028 R15: 000000000075c124 syz-executor.0 (10821) used greatest stack depth: 23408 bytes left 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 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold+0x10f/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] kmem_cache_alloc+0x2d7/0x780 mm/slab.c:3550 kmem_cache_zalloc include/linux/slab.h:651 [inline] mmu_topup_memory_cache arch/x86/kvm/mmu.c:946 [inline] mmu_topup_memory_cache arch/x86/kvm/mmu.c:938 [inline] mmu_topup_memory_caches+0x86/0x320 arch/x86/kvm/mmu.c:992 kvm_mmu_load+0x21/0xd40 arch/x86/kvm/mmu.c:4780 kvm_mmu_reload arch/x86/kvm/mmu.h:86 [inline] vcpu_enter_guest+0x2eb9/0x5220 arch/x86/kvm/x86.c:7172 vcpu_run arch/x86/kvm/x86.c:7369 [inline] kvm_arch_vcpu_ioctl_run+0x318/0x1000 arch/x86/kvm/x86.c:7536 kvm_vcpu_ioctl+0x401/0xd10 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2661 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: 0033:0x45b349 RSP: 002b:00007f6ea937bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f6ea937c6d4 RCX: 000000000045b349 RDX: 0000000000000000 RSI: 000000000000ae80 RDI: 0000000000000005 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006 R13: 000000000000039d R14: 00000000004c4dc8 R15: 0000000000000005 audit: type=1400 audit(1579597698.267:91): avc: denied { relabelfrom } for pid=11182 comm="syz-executor.1" name="" dev="pipefs" ino=50552 scontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=unconfined_u:system_r:insmod_t:s0-s0:c0.c1023 tclass=fifo_file permissive=1 NOHZ: local_softirq_pending 08