RBP: 00007ff97fa5e1d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffd3d8ff6ff R14: 00007ff97fa5e300 R15: 0000000000022000 ====================================================== WARNING: possible circular locking dependency detected 4.14.221-syzkaller #0 Not tainted ------------------------------------------------------ syz-executor.4/1469 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: [] pty_write+0xdb/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){-.-.}: __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_secondary+0x4db/0x670 arch/x86/kernel/smpboot.c:272 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 fail_dump lib/fault-inject.c:44 [inline] should_fail.cold+0xdf/0x149 lib/fault-inject.c:149 should_failslab+0xd6/0x130 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+0x6d/0x400 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] tty_buffer_alloc+0xc0/0x270 drivers/tty/tty_buffer.c:169 __tty_buffer_request_room+0x12c/0x290 drivers/tty/tty_buffer.c:267 tty_insert_flip_string_fixed_flag+0x8b/0x210 drivers/tty/tty_buffer.c:312 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x10d/0x1d0 drivers/tty/pty.c:122 n_tty_write+0x85e/0xda0 drivers/tty/n_tty.c:2356 do_tty_write drivers/tty/tty_io.c:959 [inline] tty_write+0x410/0x740 drivers/tty/tty_io.c:1043 __vfs_write+0xe4/0x630 fs/read_write.c:480 vfs_write+0x17f/0x4d0 fs/read_write.c:544 SYSC_write fs/read_write.c:590 [inline] SyS_write+0xf2/0x210 fs/read_write.c:582 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 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 *** 5 locks held by syz-executor.4/1469: #0: (&tty->ldisc_sem){++++}, at: [] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284 #1: (&tty->atomic_write_lock){+.+.}, at: [] tty_write_lock drivers/tty/tty_io.c:885 [inline] #1: (&tty->atomic_write_lock){+.+.}, at: [] do_tty_write drivers/tty/tty_io.c:908 [inline] #1: (&tty->atomic_write_lock){+.+.}, at: [] tty_write+0x22d/0x740 drivers/tty/tty_io.c:1043 #2: (&tty->termios_rwsem){++++}, at: [] n_tty_write+0x18a/0xda0 drivers/tty/n_tty.c:2316 #3: (&ldata->output_lock){+.+.}, at: [] n_tty_write+0x82b/0xda0 drivers/tty/n_tty.c:2355 #4: (&(&port->lock)->rlock){-.-.}, at: [] pty_write+0xdb/0x1d0 drivers/tty/pty.c:120 stack backtrace: CPU: 1 PID: 1469 Comm: syz-executor.4 Not tainted 4.14.221-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 fail_dump lib/fault-inject.c:44 [inline] should_fail.cold+0xdf/0x149 lib/fault-inject.c:149 should_failslab+0xd6/0x130 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+0x6d/0x400 mm/slab.c:3729 kmalloc include/linux/slab.h:493 [inline] tty_buffer_alloc+0xc0/0x270 drivers/tty/tty_buffer.c:169 __tty_buffer_request_room+0x12c/0x290 drivers/tty/tty_buffer.c:267 tty_insert_flip_string_fixed_flag+0x8b/0x210 drivers/tty/tty_buffer.c:312 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x10d/0x1d0 drivers/tty/pty.c:122 n_tty_write+0x85e/0xda0 drivers/tty/n_tty.c:2356 do_tty_write drivers/tty/tty_io.c:959 [inline] tty_write+0x410/0x740 drivers/tty/tty_io.c:1043 __vfs_write+0xe4/0x630 fs/read_write.c:480 vfs_write+0x17f/0x4d0 fs/read_write.c:544 SYSC_write fs/read_write.c:590 [inline] SyS_write+0xf2/0x210 fs/read_write.c:582 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x466019 RSP: 002b:00007ff97fa5e188 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466019 RDX: 0000000000000018 RSI: 00000000200000c0 RDI: 0000000000000003 RBP: 00007ff97fa5e1d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffd3d8ff6ff R14: 00007ff97fa5e300 R15: 0000000000022000 FAULT_INJECTION: forcing a failure. name failslab, interval 1, probability 0, space 0, times 0 CPU: 1 PID: 1490 Comm: syz-executor.3 Not tainted 4.14.221-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 fail_dump lib/fault-inject.c:51 [inline] should_fail.cold+0x10a/0x149 lib/fault-inject.c:149 should_failslab+0xd6/0x130 mm/failslab.c:32 slab_pre_alloc_hook mm/slab.h:421 [inline] slab_alloc mm/slab.c:3376 [inline] kmem_cache_alloc+0x28e/0x3c0 mm/slab.c:3550 ptlock_alloc+0x1d/0x70 mm/memory.c:4834 ptlock_init include/linux/mm.h:1764 [inline] pgtable_page_ctor include/linux/mm.h:1798 [inline] pte_alloc_one+0x57/0x100 arch/x86/mm/pgtable.c:33 __do_huge_pmd_anonymous_page mm/huge_memory.c:568 [inline] do_huge_pmd_anonymous_page+0x8fc/0x1700 mm/huge_memory.c:731 create_huge_pmd mm/memory.c:3974 [inline] __handle_mm_fault+0x2ac4/0x4620 mm/memory.c:4177 handle_mm_fault+0x391/0x860 mm/memory.c:4243 __do_page_fault+0x549/0xad0 arch/x86/mm/fault.c:1442 page_fault+0x25/0x50 arch/x86/entry/entry_64.S:1123 RIP: 0010:copy_user_generic_unrolled+0x89/0xc0 arch/x86/lib/copy_user_64.S:67 RSP: 0018:ffff8880975ffdf0 EFLAGS: 00010202 RAX: ffffed1012ebffcb RBX: 0000000000000010 RCX: 0000000000000002 RDX: 0000000000000000 RSI: ffff8880975ffe48 RDI: 0000000020000000 RBP: ffff8880975ffe48 R08: 0000000000000000 R09: ffffed1012ebffca R10: ffff8880975ffe57 R11: ffff8880a7014000 R12: 0000000020000000 R13: 00007ffffffff000 R14: 0000000020000010 R15: 0000000000000000 copy_user_generic arch/x86/include/asm/uaccess_64.h:37 [inline] raw_copy_to_user arch/x86/include/asm/uaccess_64.h:112 [inline] _copy_to_user+0xaa/0xd0 lib/usercopy.c:28 copy_to_user include/linux/uaccess.h:155 [inline] put_timespec64+0x9e/0xf0 kernel/time/time.c:920 SYSC_clock_gettime kernel/time/posix-timers.c:1075 [inline] SyS_clock_gettime+0x128/0x180 kernel/time/posix-timers.c:1063 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x46/0xbb RIP: 0033:0x466019 RSP: 002b:00007f850bacf188 EFLAGS: 00000246 ORIG_RAX: 00000000000000e4 RAX: ffffffffffffffda RBX: 000000000056bf60 RCX: 0000000000466019 RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000002 RBP: 00007f850bacf1d0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 R13: 00007ffff32c167f R14: 00007f850bacf300 R15: 0000000000022000