IPv6: ADDRCONF(NETDEV_CHANGE): veth1_to_bridge: link becomes ready IPv6: ADDRCONF(NETDEV_UP): veth0: link is not ready IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready INFO: task syz-executor0:4172 blocked for more than 120 seconds. Not tainted 4.9.109-ge1815b3 #3 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor0 D28912 4172 3795 0x20020004 ffff8801d3ff8000 ffff8801d8759a40 ffff8801d3f7b480 ffff8801d8a99800 ffff8801db221c18 ffff8801d390fb90 ffffffff839e8a8d 0000000000000002 0000000041b58ab3 ffffffff843b9d9b 00ffffff81221500 ffff8801db2224e8 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3557 [] blk_mq_freeze_queue_wait+0x114/0x230 block/blk-mq.c:75 [] blk_freeze_queue block/blk-mq.c:92 [inline] [] blk_mq_freeze_queue+0x1d/0x20 block/blk-mq.c:101 [] loop_switch drivers/block/loop.c:599 [inline] [] loop_change_fd drivers/block/loop.c:685 [inline] [] lo_ioctl+0x722/0x1aa0 drivers/block/loop.c:1350 [] lo_compat_ioctl+0xb2/0x140 drivers/block/loop.c:1540 [] compat_blkdev_ioctl+0x3a5/0x3ad0 block/compat_ioctl.c:751 [] C_SYSC_ioctl fs/compat_ioctl.c:1602 [inline] [] compat_SyS_ioctl+0x126/0x1fe0 fs/compat_ioctl.c:1549 [] do_syscall_32_irqs_on arch/x86/entry/common.c:325 [inline] [] do_fast_syscall_32+0x2f7/0x870 arch/x86/entry/common.c:387 [] entry_SYSENTER_compat+0x90/0xa2 arch/x86/entry/entry_64_compat.S:137 Showing all locks held in the system: 2 locks held by khungtaskd/519: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x11c/0xa20 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336 2 locks held by getty/3645: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2133 1 lock held by syz-executor0/4172: #0: (&lo->lo_ctl_mutex/1){+.+.+.}, at: [] lo_ioctl+0x8b/0x1aa0 drivers/block/loop.c:1344 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 519 Comm: khungtaskd Not tainted 4.9.109-ge1815b3 #3 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d8557d08 ffffffff81eb3e29 0000000000000000 0000000000000000 0000000000000000 0000000000000001 ffffffff810b9580 ffff8801d8557d40 ffffffff81ebf127 0000000000000000 0000000000000000 0000000000000002 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60 [] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [] check_hung_task kernel/hung_task.c:125 [inline] [] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [] watchdog+0x6b4/0xa20 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at pc 0xffffffff839f8596