hid-generic 0000:0000:0004.009F: unknown main item tag 0x0
 __should_failslab+0x124/0x180 mm/failslab.c:32
IRQs not enabled as expected
 should_failslab+0x9/0x14 mm/slab_common.c:1576
 slab_pre_alloc_hook mm/slab.h:423 [inline]
 slab_alloc mm/slab.c:3365 [inline]
 __do_kmalloc mm/slab.c:3707 [inline]
 __kmalloc+0x70/0x760 mm/slab.c:3718
WARNING: CPU: 0 PID: 3729 at fs/eventpoll.c:1756 ep_poll+0x6a1/0x15d0 fs/eventpoll.c:1756
Kernel panic - not syncing: panic_on_warn set ...
 kmalloc include/linux/slab.h:550 [inline]
 tty_buffer_alloc drivers/tty/tty_buffer.c:175 [inline]
 __tty_buffer_request_room+0x2da/0x810 drivers/tty/tty_buffer.c:273
 tty_insert_flip_string_fixed_flag+0x88/0x1f0 drivers/tty/tty_buffer.c:318
 tty_insert_flip_string include/linux/tty_flip.h:37 [inline]
 pty_write+0x12c/0x1f0 drivers/tty/pty.c:122
 tty_put_char+0x137/0x160 drivers/tty/tty_io.c:3022
 __process_echoes+0x1cc/0x9b0 drivers/tty/n_tty.c:744
 flush_echoes drivers/tty/n_tty.c:827 [inline]
 __receive_buf drivers/tty/n_tty.c:1646 [inline]
 n_tty_receive_buf_common+0x154d/0x2de0 drivers/tty/n_tty.c:1740
 n_tty_receive_buf+0x30/0x40 drivers/tty/n_tty.c:1769
 tiocsti drivers/tty/tty_io.c:2186 [inline]
 tty_ioctl+0x7cc/0x17d0 drivers/tty/tty_io.c:2562
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457569
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 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 0f 83 cb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f3c2d694c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f3c2d694c90 RCX: 0000000000457569
RDX: 0000000020000040 RSI: 0000000000005412 RDI: 0000000000000004
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f3c2d6956d4
R13: 00000000004c10cb R14: 00000000004d2288 R15: 0000000000000007
CPU: 0 PID: 3729 Comm: udevd Not tainted 4.20.0-rc5-next-20181207+ #163

======================================================
WARNING: possible circular locking dependency detected
4.20.0-rc5-next-20181207+ #163 Not tainted
------------------------------------------------------
syz-executor5/26371 is trying to acquire lock:
00000000d6d574a2 (console_owner){-.-.}, at: log_next kernel/printk/printk.c:491 [inline]
00000000d6d574a2 (console_owner){-.-.}, at: console_unlock+0x570/0x1190 kernel/printk/printk.c:2399

but task is already holding lock:
00000000d0602e9e (&(&port->lock)->rlock){-.-.}, at: pty_write+0xf9/0x1f0 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+0x99/0xd0 kernel/locking/spinlock.c:152
       tty_port_tty_get+0x20/0x80 drivers/tty/tty_port.c:287
       tty_port_default_wakeup+0x15/0x40 drivers/tty/tty_port.c:47
       tty_port_tty_wakeup+0x5d/0x70 drivers/tty/tty_port.c:387
       uart_write_wakeup+0x44/0x60 drivers/tty/serial/serial_core.c:103
       serial8250_tx_chars+0x4be/0xb60 drivers/tty/serial/8250/8250_port.c:1825
       serial8250_handle_irq.part.23+0x1c1/0x2f0 drivers/tty/serial/8250/8250_port.c:1898
       serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1884 [inline]
       serial8250_default_handle_irq+0xc8/0x150 drivers/tty/serial/8250/8250_port.c:1914
       serial8250_interrupt+0xef/0x190 drivers/tty/serial/8250/8250_core.c:125
       __handle_irq_event_percpu+0x195/0xb30 kernel/irq/handle.c:149
       handle_irq_event_percpu+0xa0/0x1d0 kernel/irq/handle.c:189
       handle_irq_event+0xa7/0x135 kernel/irq/handle.c:206
       handle_edge_irq+0x227/0x880 kernel/irq/chip.c:791
       generic_handle_irq_desc include/linux/irqdesc.h:154 [inline]
       handle_irq+0x252/0x3d8 arch/x86/kernel/irq_64.c:78
       do_IRQ+0x98/0x1c0 arch/x86/kernel/irq.c:246
       ret_from_intr+0x0/0x1e
       native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:57
       arch_safe_halt arch/x86/include/asm/paravirt.h:156 [inline]
       default_idle+0xbf/0x490 arch/x86/kernel/process.c:564
       arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:555
       default_idle_call+0x6d/0x90 kernel/sched/idle.c:93
       cpuidle_idle_call kernel/sched/idle.c:153 [inline]
       do_idle+0x49b/0x5c0 kernel/sched/idle.c:262
       cpu_startup_entry+0x18/0x20 kernel/sched/idle.c:353
       rest_init+0x243/0x372 init/main.c:442
       arch_call_rest_init+0xe/0x1b
       start_kernel+0x9f5/0xa30 init/main.c:744
       x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470
       x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:451
       secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243

-> #1 (&port_lock_key){-.-.}:
       __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline]
       _raw_spin_lock_irqsave+0x99/0xd0 kernel/locking/spinlock.c:152
       serial8250_console_write+0x877/0xad0 drivers/tty/serial/8250/8250_port.c:3264
       univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:586
       call_console_drivers kernel/printk/printk.c:1741 [inline]
       console_unlock+0xb1f/0x1190 kernel/printk/printk.c:2412
       vprintk_emit+0x391/0x990 kernel/printk/printk.c:1935
       vprintk_default+0x28/0x30 kernel/printk/printk.c:1962
       vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398
       printk+0xa7/0xcf kernel/printk/printk.c:1995
       register_console+0x8df/0xcf0 kernel/printk/printk.c:2727
       univ8250_console_init+0x3f/0x4b drivers/tty/serial/8250/8250_core.c:681
       console_init+0x6b4/0x9e7 kernel/printk/printk.c:2813
       start_kernel+0x713/0xa30 init/main.c:667
       x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:470
       x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:451
       secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:243

-> #0 (console_owner){-.-.}:
       lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844
       console_lock_spinning_enable kernel/printk/printk.c:1604 [inline]
       console_unlock+0x5dd/0x1190 kernel/printk/printk.c:2409
       vprintk_emit+0x391/0x990 kernel/printk/printk.c:1935
       vprintk_default+0x28/0x30 kernel/printk/printk.c:1962
       vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398
       printk+0xa7/0xcf kernel/printk/printk.c:1995
       fail_dump lib/fault-inject.c:44 [inline]
       should_fail+0xac1/0xd01 lib/fault-inject.c:149
       __should_failslab+0x124/0x180 mm/failslab.c:32
       should_failslab+0x9/0x14 mm/slab_common.c:1576
       slab_pre_alloc_hook mm/slab.h:423 [inline]
       slab_alloc mm/slab.c:3365 [inline]
       __do_kmalloc mm/slab.c:3707 [inline]
       __kmalloc+0x70/0x760 mm/slab.c:3718
       kmalloc include/linux/slab.h:550 [inline]
       tty_buffer_alloc drivers/tty/tty_buffer.c:175 [inline]
       __tty_buffer_request_room+0x2da/0x810 drivers/tty/tty_buffer.c:273
       tty_insert_flip_string_fixed_flag+0x88/0x1f0 drivers/tty/tty_buffer.c:318
       tty_insert_flip_string include/linux/tty_flip.h:37 [inline]
       pty_write+0x12c/0x1f0 drivers/tty/pty.c:122
       tty_put_char+0x137/0x160 drivers/tty/tty_io.c:3022
       __process_echoes+0x1cc/0x9b0 drivers/tty/n_tty.c:744
       flush_echoes drivers/tty/n_tty.c:827 [inline]
       __receive_buf drivers/tty/n_tty.c:1646 [inline]
       n_tty_receive_buf_common+0x154d/0x2de0 drivers/tty/n_tty.c:1740
       n_tty_receive_buf+0x30/0x40 drivers/tty/n_tty.c:1769
       tiocsti drivers/tty/tty_io.c:2186 [inline]
       tty_ioctl+0x7cc/0x17d0 drivers/tty/tty_io.c:2562
       vfs_ioctl fs/ioctl.c:46 [inline]
       file_ioctl fs/ioctl.c:509 [inline]
       do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
       ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
       __do_sys_ioctl fs/ioctl.c:720 [inline]
       __se_sys_ioctl fs/ioctl.c:718 [inline]
       __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
       do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

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-executor5/26371:
 #0: 000000005a6517ee (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341
 #1: 000000005262b8fc (&o_tty->termios_rwsem/1){++++}, at: n_tty_receive_buf_common+0xf9/0x2de0 drivers/tty/n_tty.c:1703
 #2: 000000000d97ab39 (&ldata->output_lock){+.+.}, at: flush_echoes drivers/tty/n_tty.c:825 [inline]
 #2: 000000000d97ab39 (&ldata->output_lock){+.+.}, at: __receive_buf drivers/tty/n_tty.c:1646 [inline]
 #2: 000000000d97ab39 (&ldata->output_lock){+.+.}, at: n_tty_receive_buf_common+0x1515/0x2de0 drivers/tty/n_tty.c:1740
 #3: 00000000d0602e9e (&(&port->lock)->rlock){-.-.}, at: pty_write+0xf9/0x1f0 drivers/tty/pty.c:120
 #4: 0000000023bed708 (console_lock){+.+.}, at: console_trylock_spinning kernel/printk/printk.c:1666 [inline]
 #4: 0000000023bed708 (console_lock){+.+.}, at: vprintk_emit+0x372/0x990 kernel/printk/printk.c:1934

stack backtrace:
CPU: 1 PID: 26371 Comm: syz-executor5 Not tainted 4.20.0-rc5-next-20181207+ #163
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x244/0x39d lib/dump_stack.c:113
 print_circular_bug.isra.35.cold.56+0x1bd/0x27d kernel/locking/lockdep.c:1221
 check_prev_add kernel/locking/lockdep.c:1863 [inline]
 check_prevs_add kernel/locking/lockdep.c:1976 [inline]
 validate_chain kernel/locking/lockdep.c:2347 [inline]
 __lock_acquire+0x3399/0x4c20 kernel/locking/lockdep.c:3341
 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844
 console_lock_spinning_enable kernel/printk/printk.c:1604 [inline]
 console_unlock+0x5dd/0x1190 kernel/printk/printk.c:2409
 vprintk_emit+0x391/0x990 kernel/printk/printk.c:1935
 vprintk_default+0x28/0x30 kernel/printk/printk.c:1962
 vprintk_func+0x7e/0x181 kernel/printk/printk_safe.c:398
 printk+0xa7/0xcf kernel/printk/printk.c:1995
 fail_dump lib/fault-inject.c:44 [inline]
 should_fail+0xac1/0xd01 lib/fault-inject.c:149
 __should_failslab+0x124/0x180 mm/failslab.c:32
 should_failslab+0x9/0x14 mm/slab_common.c:1576
 slab_pre_alloc_hook mm/slab.h:423 [inline]
 slab_alloc mm/slab.c:3365 [inline]
 __do_kmalloc mm/slab.c:3707 [inline]
 __kmalloc+0x70/0x760 mm/slab.c:3718
 kmalloc include/linux/slab.h:550 [inline]
 tty_buffer_alloc drivers/tty/tty_buffer.c:175 [inline]
 __tty_buffer_request_room+0x2da/0x810 drivers/tty/tty_buffer.c:273
 tty_insert_flip_string_fixed_flag+0x88/0x1f0 drivers/tty/tty_buffer.c:318
 tty_insert_flip_string include/linux/tty_flip.h:37 [inline]
 pty_write+0x12c/0x1f0 drivers/tty/pty.c:122
 tty_put_char+0x137/0x160 drivers/tty/tty_io.c:3022
 __process_echoes+0x1cc/0x9b0 drivers/tty/n_tty.c:744
 flush_echoes drivers/tty/n_tty.c:827 [inline]
 __receive_buf drivers/tty/n_tty.c:1646 [inline]
 n_tty_receive_buf_common+0x154d/0x2de0 drivers/tty/n_tty.c:1740
 n_tty_receive_buf+0x30/0x40 drivers/tty/n_tty.c:1769
 tiocsti drivers/tty/tty_io.c:2186 [inline]
 tty_ioctl+0x7cc/0x17d0 drivers/tty/tty_io.c:2562
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:509 [inline]
 do_vfs_ioctl+0x1de/0x1790 fs/ioctl.c:696
 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:713
 __do_sys_ioctl fs/ioctl.c:720 [inline]
 __se_sys_ioctl fs/ioctl.c:718 [inline]
 __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:718
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x457569
Code: fd b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89
Lost 7 message(s)!
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x244/0x39d lib/dump_stack.c:113
 panic+0x2ad/0x632 kernel/panic.c:214
 __warn.cold.8+0x20/0x4f kernel/panic.c:571
 report_bug+0x254/0x2d0 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:178 [inline]
 do_error_trap+0x11b/0x200 arch/x86/kernel/traps.c:271
 do_invalid_op+0x36/0x40 arch/x86/kernel/traps.c:290
 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:969
RIP: 0010:ep_poll+0x6a1/0x15d0 fs/eventpoll.c:1756
Code: ff 44 89 ee e8 f0 eb 97 ff 45 84 ed 0f 85 85 fb ff ff e8 12 eb 97 ff 48 c7 c7 80 23 56 88 c6 05 7e a1 4b 08 01 e8 4f 12 61 ff <0f> 0b e9 66 fb ff ff e8 f3 ea 97 ff 49 8d 9c 24 80 00 00 00 48 89
RSP: 0018:ffff8881c2f1f9a8 EFLAGS: 00010286
RAX: 0000000000000000 RBX: 0000000000000bb8 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffffffff81661e55 RDI: 0000000000000005
RBP: ffff8881c2f1fdb0 R08: ffff8881c2f14480 R09: fffffbfff12f2b70
R10: fffffbfff12f2b70 R11: ffffffff89795b83 R12: ffff8881c33a1300
R13: 0000000000000000 R14: 00007ffc1727eeb0 R15: 00000000ffffffea
 do_epoll_wait+0x1b0/0x200 fs/eventpoll.c:2216
 __do_sys_epoll_wait fs/eventpoll.c:2226 [inline]
 __se_sys_epoll_wait fs/eventpoll.c:2223 [inline]
 __x64_sys_epoll_wait+0x97/0xf0 fs/eventpoll.c:2223
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7f86fcffb943
Code: 00 31 d2 48 29 c2 64 89 11 48 83 c8 ff eb ea 90 90 90 90 90 90 90 90 83 3d b5 dc 2a 00 00 75 13 49 89 ca b8 e8 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 34 c3 48 83 ec 08 e8 3b c4 00 00 48 89 04 24
RSP: 002b:00007ffc1727edb8 EFLAGS: 00000246 ORIG_RAX: 00000000000000e8
RAX: ffffffffffffffda RBX: 0000000000000bb8 RCX: 00007f86fcffb943
RDX: 0000000000000008 RSI: 00007ffc1727eeb0 RDI: 000000000000000a
RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000001
R10: 0000000000000bb8 R11: 0000000000000246 R12: 0000000000000003
R13: 0000000000000000 R14: 0000000001e70e30 R15: 0000000001e69250
Kernel Offset: disabled
Rebooting in 86400 seconds..