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+0x1c9/0x2b4 lib/dump_stack.c:113 IRQs not enabled as expected fail_dump lib/fault-inject.c:51 [inline] should_fail.cold.4+0xa/0x11 lib/fault-inject.c:149 WARNING: CPU: 1 PID: 10172 at kernel/softirq.c:169 __local_bh_enable_ip+0x1bb/0x230 kernel/softirq.c:169 Kernel panic - not syncing: panic_on_warn set ... __should_failslab+0x124/0x180 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1557 slab_pre_alloc_hook mm/slab.h:423 [inline] slab_alloc mm/slab.c:3378 [inline] __do_kmalloc mm/slab.c:3716 [inline] __kmalloc+0x63/0x720 mm/slab.c:3727 kmalloc include/linux/slab.h:518 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:170 [inline] __tty_buffer_request_room+0x2da/0x810 drivers/tty/tty_buffer.c:268 tty_insert_flip_string_fixed_flag+0x8d/0x1f0 drivers/tty/tty_buffer.c:313 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x12c/0x1f0 drivers/tty/pty.c:121 tty_put_char+0x137/0x160 drivers/tty/tty_io.c:2865 __process_echoes+0x462/0x9b0 drivers/tty/n_tty.c:714 flush_echoes drivers/tty/n_tty.c:814 [inline] __receive_buf drivers/tty/n_tty.c:1633 [inline] n_tty_receive_buf_common+0x11d3/0x2c70 drivers/tty/n_tty.c:1727 n_tty_receive_buf+0x30/0x40 drivers/tty/n_tty.c:1756 tiocsti drivers/tty/tty_io.c:2171 [inline] tty_ioctl+0x7e7/0x1870 drivers/tty/tty_io.c:2557 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 __do_sys_ioctl fs/ioctl.c:709 [inline] __se_sys_ioctl fs/ioctl.c:707 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457099 Code: fd b4 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 b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f7cf6e7dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 00007f7cf6e7e6d4 RCX: 0000000000457099 RDX: 0000000020000040 RSI: 0000000000005412 RDI: 0000000000000004 RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000006 R13: 00000000004d0df8 R14: 00000000004c6736 R15: 0000000000000000 CPU: 1 PID: 10172 Comm: syz-executor7 Not tainted 4.19.0-rc2-next-20180904+ #55 ====================================================== WARNING: possible circular locking dependency detected 4.19.0-rc2-next-20180904+ #55 Not tainted ------------------------------------------------------ syz-executor5/10168 is trying to acquire lock: 0000000024f4e687 (console_owner){-.-.}, at: log_next kernel/printk/printk.c:498 [inline] 0000000024f4e687 (console_owner){-.-.}, at: console_unlock+0x7a7/0x10d0 kernel/printk/printk.c:2394 but task is already holding lock: 0000000010640b20 (&(&port->lock)->rlock){-.-.}, at: pty_write+0xf9/0x1f0 drivers/tty/pty.c:119 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+0x96/0xc0 kernel/locking/spinlock.c:152 tty_port_tty_get+0x20/0x80 drivers/tty/tty_port.c:288 tty_port_default_wakeup+0x15/0x40 drivers/tty/tty_port.c:47 tty_port_tty_wakeup+0x5d/0x70 drivers/tty/tty_port.c:390 uart_write_wakeup+0x44/0x60 drivers/tty/serial/serial_core.c:103 serial8250_tx_chars+0x4be/0xb60 drivers/tty/serial/8250/8250_port.c:1806 serial8250_handle_irq.part.23+0x1ee/0x280 drivers/tty/serial/8250/8250_port.c:1879 serial8250_handle_irq drivers/tty/serial/8250/8250_port.c:1865 [inline] serial8250_default_handle_irq+0xc8/0x150 drivers/tty/serial/8250/8250_port.c:1895 serial8250_interrupt+0xfa/0x1d0 drivers/tty/serial/8250/8250_core.c:125 __handle_irq_event_percpu+0x1c8/0xa50 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+0x20f/0x870 kernel/irq/chip.c:791 generic_handle_irq_desc include/linux/irqdesc.h:154 [inline] handle_irq+0x18c/0x2e7 arch/x86/kernel/irq_64.c:78 do_IRQ+0x80/0x1a0 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:94 [inline] default_idle+0xc2/0x410 arch/x86/kernel/process.c:498 arch_cpu_idle+0x10/0x20 arch/x86/kernel/process.c:489 default_idle_call+0x6d/0x90 kernel/sched/idle.c:93 cpuidle_idle_call kernel/sched/idle.c:153 [inline] do_idle+0x3aa/0x580 kernel/sched/idle.c:262 cpu_startup_entry+0x10c/0x120 kernel/sched/idle.c:368 start_secondary+0x433/0x5d0 arch/x86/kernel/smpboot.c:271 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242 -> #1 (&port_lock_key){-.-.}: __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:110 [inline] _raw_spin_lock_irqsave+0x96/0xc0 kernel/locking/spinlock.c:152 serial8250_console_write+0x8e5/0xb20 drivers/tty/serial/8250/8250_port.c:3247 univ8250_console_write+0x5f/0x70 drivers/tty/serial/8250/8250_core.c:590 call_console_drivers kernel/printk/printk.c:1725 [inline] console_unlock+0xace/0x10d0 kernel/printk/printk.c:2407 vprintk_emit+0x33a/0x910 kernel/printk/printk.c:1926 vprintk_default+0x28/0x30 kernel/printk/printk.c:1967 vprintk_func+0x7a/0x117 kernel/printk/printk_safe.c:398 printk+0xa7/0xcf kernel/printk/printk.c:2000 register_console+0x7e7/0xc00 kernel/printk/printk.c:2722 univ8250_console_init+0x3f/0x4b drivers/tty/serial/8250/8250_core.c:685 console_init+0x5d4/0x891 kernel/printk/printk.c:2808 start_kernel+0x610/0x94e init/main.c:661 x86_64_start_reservations+0x29/0x2b arch/x86/kernel/head64.c:452 x86_64_start_kernel+0x76/0x79 arch/x86/kernel/head64.c:433 secondary_startup_64+0xa4/0xb0 arch/x86/kernel/head_64.S:242 -> #0 (console_owner){-.-.}: lock_acquire+0x1e4/0x4f0 kernel/locking/lockdep.c:3901 console_lock_spinning_enable kernel/printk/printk.c:1588 [inline] console_unlock+0x814/0x10d0 kernel/printk/printk.c:2404 vprintk_emit+0x33a/0x910 kernel/printk/printk.c:1926 vprintk_default+0x28/0x30 kernel/printk/printk.c:1967 vprintk_func+0x7a/0x117 kernel/printk/printk_safe.c:398 printk+0xa7/0xcf kernel/printk/printk.c:2000 fail_dump lib/fault-inject.c:44 [inline] should_fail+0xb04/0xd86 lib/fault-inject.c:149 __should_failslab+0x124/0x180 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1557 slab_pre_alloc_hook mm/slab.h:423 [inline] slab_alloc mm/slab.c:3378 [inline] __do_kmalloc mm/slab.c:3716 [inline] __kmalloc+0x63/0x720 mm/slab.c:3727 kmalloc include/linux/slab.h:518 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:170 [inline] __tty_buffer_request_room+0x2da/0x810 drivers/tty/tty_buffer.c:268 tty_insert_flip_string_fixed_flag+0x8d/0x1f0 drivers/tty/tty_buffer.c:313 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x12c/0x1f0 drivers/tty/pty.c:121 tty_put_char+0x137/0x160 drivers/tty/tty_io.c:2865 __process_echoes+0x462/0x9b0 drivers/tty/n_tty.c:714 flush_echoes drivers/tty/n_tty.c:814 [inline] __receive_buf drivers/tty/n_tty.c:1633 [inline] n_tty_receive_buf_common+0x11d3/0x2c70 drivers/tty/n_tty.c:1727 n_tty_receive_buf+0x30/0x40 drivers/tty/n_tty.c:1756 tiocsti drivers/tty/tty_io.c:2171 [inline] tty_ioctl+0x7e7/0x1870 drivers/tty/tty_io.c:2557 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 __do_sys_ioctl fs/ioctl.c:709 [inline] __se_sys_ioctl fs/ioctl.c:707 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 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-executor5/10168: #0: 000000000d2dc9cb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000009f357d4f (&o_tty->termios_rwsem/1){++++}, at: n_tty_receive_buf_common+0xeb/0x2c70 drivers/tty/n_tty.c:1690 #2: 0000000005bec1a7 (&ldata->output_lock){+.+.}, at: flush_echoes drivers/tty/n_tty.c:812 [inline] #2: 0000000005bec1a7 (&ldata->output_lock){+.+.}, at: __receive_buf drivers/tty/n_tty.c:1633 [inline] #2: 0000000005bec1a7 (&ldata->output_lock){+.+.}, at: n_tty_receive_buf_common+0x119b/0x2c70 drivers/tty/n_tty.c:1727 #3: 0000000010640b20 (&(&port->lock)->rlock){-.-.}, at: pty_write+0xf9/0x1f0 drivers/tty/pty.c:119 #4: 0000000073842333 (console_lock){+.+.}, at: console_trylock_spinning kernel/printk/printk.c:1650 [inline] #4: 0000000073842333 (console_lock){+.+.}, at: vprintk_emit+0x31f/0x910 kernel/printk/printk.c:1925 stack backtrace: CPU: 0 PID: 10168 Comm: syz-executor5 Not tainted 4.19.0-rc2-next-20180904+ #55 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+0x1c9/0x2b4 lib/dump_stack.c:113 print_circular_bug.isra.34.cold.55+0x1bd/0x27d kernel/locking/lockdep.c:1222 check_prev_add kernel/locking/lockdep.c:1862 [inline] check_prevs_add kernel/locking/lockdep.c:1975 [inline] validate_chain kernel/locking/lockdep.c:2416 [inline] __lock_acquire+0x3449/0x5020 kernel/locking/lockdep.c:3412 lock_acquire+0x1e4/0x4f0 kernel/locking/lockdep.c:3901 console_lock_spinning_enable kernel/printk/printk.c:1588 [inline] console_unlock+0x814/0x10d0 kernel/printk/printk.c:2404 vprintk_emit+0x33a/0x910 kernel/printk/printk.c:1926 vprintk_default+0x28/0x30 kernel/printk/printk.c:1967 vprintk_func+0x7a/0x117 kernel/printk/printk_safe.c:398 printk+0xa7/0xcf kernel/printk/printk.c:2000 fail_dump lib/fault-inject.c:44 [inline] should_fail+0xb04/0xd86 lib/fault-inject.c:149 __should_failslab+0x124/0x180 mm/failslab.c:32 should_failslab+0x9/0x14 mm/slab_common.c:1557 slab_pre_alloc_hook mm/slab.h:423 [inline] slab_alloc mm/slab.c:3378 [inline] __do_kmalloc mm/slab.c:3716 [inline] __kmalloc+0x63/0x720 mm/slab.c:3727 kmalloc include/linux/slab.h:518 [inline] tty_buffer_alloc drivers/tty/tty_buffer.c:170 [inline] __tty_buffer_request_room+0x2da/0x810 drivers/tty/tty_buffer.c:268 tty_insert_flip_string_fixed_flag+0x8d/0x1f0 drivers/tty/tty_buffer.c:313 tty_insert_flip_string include/linux/tty_flip.h:37 [inline] pty_write+0x12c/0x1f0 drivers/tty/pty.c:121 tty_put_char+0x137/0x160 drivers/tty/tty_io.c:2865 __process_echoes+0x462/0x9b0 drivers/tty/n_tty.c:714 flush_echoes drivers/tty/n_tty.c:814 [inline] __receive_buf drivers/tty/n_tty.c:1633 [inline] n_tty_receive_buf_common+0x11d3/0x2c70 drivers/tty/n_tty.c:1727 n_tty_receive_buf+0x30/0x40 drivers/tty/n_tty.c:1756 tiocsti drivers/tty/tty_io.c:2171 [inline] tty_ioctl+0x7e7/0x1870 drivers/tty/tty_io.c:2557 vfs_ioctl fs/ioctl.c:46 [inline] file_ioctl fs/ioctl.c:501 [inline] do_vfs_ioctl+0x1de/0x1720 fs/ioctl.c:685 ksys_ioctl+0xa9/0xd0 fs/ioctl.c:702 __do_sys_ioctl fs/ioctl.c:709 [inline] __se_sys_ioctl fs/ioctl.c:707 [inline] __x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:707 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457099 Code: fd b4 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 f 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+0x1c9/0x2b4 lib/dump_stack.c:113 panic+0x238/0x4e7 kernel/panic.c:184 __warn.cold.8+0x163/0x1ba kernel/panic.c:536 report_bug+0x252/0x2d0 lib/bug.c:186 fixup_bug arch/x86/kernel/traps.c:178 [inline] do_error_trap+0x1fc/0x4d0 arch/x86/kernel/traps.c:296 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:316 invalid_op+0x14/0x20 arch/x86/entry/entry_64.S:996 RIP: 0010:__local_bh_enable_ip+0x1bb/0x230 kernel/softirq.c:169 Code: 44 00 00 5b 41 5c 41 5d 5d c3 80 3d b6 e2 61 07 00 0f 85 3c ff ff ff 48 c7 c7 40 f4 28 87 c6 05 a2 e2 61 07 01 e8 a5 26 fe ff <0f> 0b e9 22 ff ff ff 4c 89 e7 e8 d6 56 16 00 e9 68 ff ff ff 0f 0b RSP: 0018:ffff880189fa5cb8 EFLAGS: 00010282 RAX: 0000000000000000 RBX: 0000000000000201 RCX: ffffc9000288c000 RDX: 0000000000040000 RSI: ffffffff8163ba91 RDI: ffff880189fa59a8 RBP: ffff880189fa5cd0 R08: ffff880188bd2140 R09: fffffbfff1031404 R10: fffffbfff1031404 R11: ffffffff8818a023 R12: ffffffff8608e7f4 R13: ffff880188bd2140 R14: ffffc90011f27060 R15: dffffc0000000000 __raw_read_unlock_bh include/linux/rwlock_api_smp.h:251 [inline] _raw_read_unlock_bh+0x30/0x40 kernel/locking/spinlock.c:272 ebt_do_table+0x1c14/0x2170 net/bridge/netfilter/ebtables.c:307 ebt_nat_in+0x65/0x80 net/bridge/netfilter/ebtable_nat.c:64 ebt_nat_out+0x25/0x30 net/bridge/netfilter/ebtable_nat.c:64 nf_hook_entry_hookfn include/linux/netfilter.h:119 [inline] nf_hook_slow+0xc2/0x1c0 net/netfilter/core.c:511 nf_hook include/linux/netfilter.h:242 [inline] NF_HOOK include/linux/netfilter.h:285 [inline] __br_forward+0x534/0xdc0 net/bridge/br_forward.c:113 br_flood+0x85b/0x990 net/bridge/br_forward.c:240 br_dev_xmit+0x111b/0x1810 net/bridge/br_device.c:103 ? 0xffffffff81000000 __netdev_start_xmit include/linux/netdevice.h:4313 [inline] netdev_start_xmit include/linux/netdevice.h:4322 [inline] xmit_one net/core/dev.c:3216 [inline] dev_hard_start_xmit+0x272/0xc10 net/core/dev.c:3232 __dev_queue_xmit+0x2ab2/0x3870 net/core/dev.c:3802 dev_queue_xmit+0x17/0x20 net/core/dev.c:3835 neigh_hh_output include/net/neighbour.h:473 [inline] neigh_output include/net/neighbour.h:481 [inline] ip_finish_output2+0x1063/0x1860 net/ipv4/ip_output.c:229 ip_do_fragment+0x21a2/0x2ae0 net/ipv4/ip_output.c:678 ip_fragment.constprop.49+0x179/0x240 net/ipv4/ip_output.c:549 ip_finish_output+0x6e4/0xfa0 net/ipv4/ip_output.c:315 NF_HOOK_COND include/linux/netfilter.h:276 [inline] ip_output+0x223/0x880 net/ipv4/ip_output.c:405 dst_output include/net/dst.h:444 [inline] ip_local_out+0xc5/0x1b0 net/ipv4/ip_output.c:124 ip_send_skb+0x40/0xe0 net/ipv4/ip_output.c:1441 udp_send_skb.isra.41+0x6b7/0x11d0 net/ipv4/udp.c:829 udp_push_pending_frames+0x5c/0xf0 net/ipv4/udp.c:857 udp_sendmsg+0x178a/0x38e0 net/ipv4/udp.c:1148 udpv6_sendmsg+0x296a/0x36b0 net/ipv6/udp.c:1201 inet_sendmsg+0x1a1/0x690 net/ipv4/af_inet.c:798 sock_sendmsg_nosec net/socket.c:622 [inline] sock_sendmsg+0xd5/0x120 net/socket.c:632 __sys_sendto+0x3d7/0x670 net/socket.c:1787 __do_sys_sendto net/socket.c:1799 [inline] __se_sys_sendto net/socket.c:1795 [inline] __x64_sys_sendto+0xe1/0x1a0 net/socket.c:1795 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457099 Code: fd b4 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 b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f0550d94c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f0550d956d4 RCX: 0000000000457099 RDX: 0000000000000000 RSI: 0000000020000300 RDI: 0000000000000004 RBP: 00000000009300a0 R08: 00000000200002c0 R09: 000000000000001c R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d4cc8 R14: 00000000004c91af R15: 0000000000000000 Dumping ftrace buffer: (ftrace buffer empty) Kernel Offset: disabled Rebooting in 86400 seconds..