RDX: 0000000000000004 RSI: 0000000000004c00 RDI: 0000000000000005 RBP: 0000000000000000 R08: 00007f4b07230ac8 R09: 0000000000000000 R10: 00007f4b07230acc R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000004 R14: 0000000000000004 R15: 0000000020000310 ====================================================== WARNING: possible circular locking dependency detected 4.14.217-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.3/5782 is trying to acquire lock: (console_owner){-.-.}, at: [] console_trylock_spinning kernel/printk/printk.c:1658 [inline] (console_owner){-.-.}, at: [] vprintk_emit+0x32a/0x620 kernel/printk/printk.c:1922 but task is already holding lock: (&(&port->lock)->rlock){-.-.}, at: [] tty_port_close_start.part.0+0x28/0x4c0 drivers/tty/tty_port.c:573 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (&(&port->lock)->rlock){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:160 tty_port_tty_get+0x1d/0x80 drivers/tty/tty_port.c:288 tty_port_default_wakeup+0x11/0x40 drivers/tty/tty_port.c:46 serial8250_tx_chars+0x3fe/0xbf0 drivers/tty/serial/8250/8250_port.c:1810 serial8250_handle_irq.part.0+0x28d/0x330 drivers/tty/serial/8250/8250_port.c:1897 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1870 [inline] serial8250_default_handle_irq+0x8a/0x1f0 drivers/tty/serial/8250/8250_port.c:1913 serial8250_interrupt+0xf3/0x210 drivers/tty/serial/8250/8250_core.c:129 __handle_irq_event_percpu+0xee/0x7f0 kernel/irq/handle.c:147 handle_irq_event_percpu kernel/irq/handle.c:187 [inline] handle_irq_event+0xf0/0x250 kernel/irq/handle.c:204 handle_edge_irq+0x224/0xc40 kernel/irq/chip.c:770 generic_handle_irq_desc include/linux/irqdesc.h:159 [inline] handle_irq+0x35/0x50 arch/x86/kernel/irq_64.c:87 do_IRQ+0x93/0x1d0 arch/x86/kernel/irq.c:230 ret_from_intr+0x0/0x1e native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60 arch_safe_halt arch/x86/include/asm/paravirt.h:94 [inline] default_idle+0x47/0x370 arch/x86/kernel/process.c:558 cpuidle_idle_call kernel/sched/idle.c:156 [inline] do_idle+0x250/0x3c0 kernel/sched/idle.c:246 cpu_startup_entry+0x14/0x20 kernel/sched/idle.c:351 start_kernel+0x750/0x770 init/main.c:708 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240 -> #1 (&port_lock_key){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x8c/0xc0 kernel/locking/spinlock.c:160 serial8250_console_write+0x7a7/0x9d0 drivers/tty/serial/8250/8250_port.c:3253 call_console_drivers kernel/printk/printk.c:1725 [inline] console_unlock+0x99d/0xf20 kernel/printk/printk.c:2400 vprintk_emit+0x224/0x620 kernel/printk/printk.c:1923 vprintk_func+0x58/0x160 kernel/printk/printk_safe.c:401 printk+0x9e/0xbc kernel/printk/printk.c:1996 register_console+0x6f4/0xad0 kernel/printk/printk.c:2719 univ8250_console_init+0x2f/0x3a drivers/tty/serial/8250/8250_core.c:691 console_init+0x46/0x53 kernel/printk/printk.c:2800 start_kernel+0x52e/0x770 init/main.c:634 secondary_startup_64+0xa5/0xb0 arch/x86/kernel/head_64.S:240 -> #0 (console_owner){-.-.}: lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 console_trylock_spinning kernel/printk/printk.c:1679 [inline] vprintk_emit+0x367/0x620 kernel/printk/printk.c:1922 vprintk_func+0x58/0x160 kernel/printk/printk_safe.c:401 printk+0x9e/0xbc kernel/printk/printk.c:1996 tty_port_close_start.part.0+0x46c/0x4c0 drivers/tty/tty_port.c:575 tty_port_close_start drivers/tty/tty_port.c:647 [inline] tty_port_close+0x3b/0x130 drivers/tty/tty_port.c:640 tty_release+0x40b/0x10d0 drivers/tty/tty_io.c:1670 __fput+0x25f/0x7a0 fs/file_table.c:210 task_work_run+0x11f/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 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+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb 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.3/5782: #0: (&tty->legacy_mutex){+.+.}, at: [] tty_lock+0x5f/0x70 drivers/tty/tty_mutex.c:19 #1: (&(&port->lock)->rlock){-.-.}, at: [] tty_port_close_start.part.0+0x28/0x4c0 drivers/tty/tty_port.c:573 stack backtrace: CPU: 1 PID: 5782 Comm: syz-executor.3 Not tainted 4.14.217-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+0x1b2/0x281 lib/dump_stack.c:58 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1258 check_prev_add kernel/locking/lockdep.c:1905 [inline] check_prevs_add kernel/locking/lockdep.c:2022 [inline] validate_chain kernel/locking/lockdep.c:2464 [inline] __lock_acquire+0x2e0e/0x3f20 kernel/locking/lockdep.c:3491 lock_acquire+0x170/0x3f0 kernel/locking/lockdep.c:3998 console_trylock_spinning kernel/printk/printk.c:1679 [inline] vprintk_emit+0x367/0x620 kernel/printk/printk.c:1922 vprintk_func+0x58/0x160 kernel/printk/printk_safe.c:401 printk+0x9e/0xbc kernel/printk/printk.c:1996 tty_port_close_start.part.0+0x46c/0x4c0 drivers/tty/tty_port.c:575 tty_port_close_start drivers/tty/tty_port.c:647 [inline] tty_port_close+0x3b/0x130 drivers/tty/tty_port.c:640 tty_release+0x40b/0x10d0 drivers/tty/tty_io.c:1670 __fput+0x25f/0x7a0 fs/file_table.c:210 task_work_run+0x11f/0x190 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:191 [inline] exit_to_usermode_loop+0x1ad/0x200 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+0x4a3/0x640 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x417b71 RSP: 002b:00007ffeb28657d0 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000417b71 RDX: 0000000000000000 RSI: 0000000080000000 RDI: 0000000000000004 RBP: 0000000000000001 R08: 0000000000000419 R09: 000000005290041d R10: 00007ffeb28658b0 R11: 0000000000000293 R12: ffffffffffffffff R13: 00000000000795b9 R14: 00000000000003e8 R15: 000000000119bf8c FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value jfs: Unrecognized mount option "disxF`¾" or missing value tmpfs: Bad value 'egm46633' for mount option 'nr_blocks' FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value jfs: Unrecognized mount option "disxF`¾" or missing value vxfs: WRONG superblock magic 00000000 at 1 vxfs: WRONG superblock magic 00000000 at 8 vxfs: can't find superblock. vxfs: WRONG superblock magic 00000000 at 1 FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value vxfs: WRONG superblock magic 00000000 at 8 vxfs: can't find superblock. vxfs: WRONG superblock magic 00000000 at 1 vxfs: WRONG superblock magic 00000000 at 8 vxfs: can't find superblock. jfs: Unrecognized mount option "d" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value jfs: Unrecognized mount option "d" or missing value jfs: Unrecognized mount option "discar*Å¼Ö1HpcûPd" or missing value jfs: Unrecognized mount option "discar*Å¼Ö1HpcûPd" or missing value print_req_error: I/O error, dev loop5, sector 0 IPVS: Unknown mcast interface: print_req_error: I/O error, dev loop5, sector 0 IPVS: Unknown mcast interface: print_req_error: I/O error, dev loop5, sector 0 caif:caif_disconnect_client(): nothing to disconnect print_req_error: I/O error, dev loop5, sector 0 caif:caif_disconnect_client(): nothing to disconnect jfs: Unrecognized mount option "dÇ" or missing value jfs: Unrecognized mount option "dÇ" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value jfs: Unrecognized mount option "discard<" or missing value jfs: Unrecognized mount option "discard<" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value jfs: Unrecognized mount option "dƒsN±‡ürÌ†jÍ¸´Æcard" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value jfs: Unrecognized mount option "dƒsN±‡ürÌ†jÍ¸´Æcard" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value vxfs: WRONG superblock magic 00000000 at 1 vxfs: WRONG superblock magic 00000000 at 8 vxfs: can't find superblock. FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value jfs: Unrecognized mount option "ÿÿÿÿ" or missing value jfs: Unrecognized mount option "ÿÿÿÿ" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value vxfs: WRONG superblock magic 00000000 at 1 vxfs: WRONG superblock magic 00000000 at 8 vxfs: can't find superblock. FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value print_req_error: I/O error, dev loop2, sector 0 FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value jfs: Unrecognized mount option "diacerd" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value jfs: Unrecognized mount option "diacerd" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value FAT-fs (loop5): Unrecognized mount option "obj_user=" or missing value jfs: Unrecognized mount option "dyscard" or missing value FAT-fs (loop5): bogus number of reserved sectors FAT-fs (loop5): Can't find a valid FAT filesystem Bluetooth: hci0 command 0x0406 tx timeout vxfs: WRONG superblock magic 00000000 at 1 vxfs: WRONG superblock magic 00000000 at 8 vxfs: can't find superblock. vxfs: WRONG superblock magic 00000000 at 1 vxfs: WRONG superblock magic 00000000 at 8 vxfs: can't find superblock.