Dead loop on virtual device ip6_vti0, fix it urgently! INFO: task syz-executor.5:2131 blocked for more than 140 seconds. Not tainted 4.9.169+ #42 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.5 D25032 2131 1 0x00000004 ffff8801cdb6c740 ffff8801d10cc200 ffff8801db721000 ffff8801d9924740 ffff8801db721018 ffff8801ae90fa28 ffffffff8280152e 0000000041b58ab3 ffffffff82e2b8b0 00ffffff81200360 ffff8801db7218f0 1ffff10035d21f34 Call Trace: [<00000000b1f0a13b>] schedule+0x92/0x1c0 kernel/sched/core.c:3546 [<0000000045f0cc0f>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3579 [<0000000071e155a7>] __mutex_lock_common kernel/locking/mutex.c:582 [inline] [<0000000071e155a7>] mutex_lock_nested+0x38d/0x920 kernel/locking/mutex.c:621 [<000000007c250a91>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 [<00000000400cf94b>] __blkdev_driver_ioctl block/ioctl.c:294 [inline] [<00000000400cf94b>] blkdev_ioctl+0xe14/0x19e0 block/ioctl.c:590 [<00000000406e8e81>] block_ioctl+0xde/0x120 fs/block_dev.c:1696 [<00000000d91da9e8>] vfs_ioctl fs/ioctl.c:43 [inline] [<00000000d91da9e8>] file_ioctl fs/ioctl.c:493 [inline] [<00000000d91da9e8>] do_vfs_ioctl+0xb87/0x11d0 fs/ioctl.c:677 [<00000000bae1b37b>] SYSC_ioctl fs/ioctl.c:694 [inline] [<00000000bae1b37b>] SyS_ioctl+0x8f/0xc0 fs/ioctl.c:685 [<0000000052ca84fc>] do_syscall_64+0x1ad/0x570 arch/x86/entry/common.c:285 [<0000000056b1c295>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Showing all locks held in the system: 2 locks held by khungtaskd/24: #0: (rcu_read_lock){......}, at: [<00000000b7d201aa>] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [<00000000b7d201aa>] watchdog+0x13c/0xae0 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [<000000008829515d>] debug_show_all_locks+0x7f/0x21f kernel/locking/lockdep.c:4339 2 locks held by getty/2044: #0: (&tty->ldisc_sem){++++++}, at: [<00000000df986480>] ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:377 #1: (&ldata->atomic_read_lock){+.+...}, at: [<0000000082659a5f>] n_tty_read+0x1fe/0x1820 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.5/2131: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<000000007c250a91>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 1 lock held by syz-executor.4/2136: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000062f8c58a>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 2 locks held by syz-executor.2/2139: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000062f8c58a>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<000000004243acde>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 2 locks held by syz-executor.3/2152: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000062f8c58a>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<000000004243acde>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 2 locks held by syz-executor.0/7868: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000062f8c58a>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<000000004243acde>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 3 locks held by blkid/27606: #0: (&bdev->bd_mutex){+.+.+.}, at: [<000000000176fdc3>] __blkdev_put+0xbb/0x840 fs/block_dev.c:1587 #1: (loop_index_mutex){+.+.+.}, at: [<00000000e4e083cb>] lo_release+0x1e/0x1b0 drivers/block/loop.c:1664 #2: (loop_ctl_mutex#2){+.+.+.}, at: [<0000000038735bf6>] __lo_release drivers/block/loop.c:1642 [inline] #2: (loop_ctl_mutex#2){+.+.+.}, at: [<0000000038735bf6>] lo_release+0x84/0x1b0 drivers/block/loop.c:1665 2 locks held by syz-executor.1/27608: #0: (loop_ctl_mutex/1){+.+.+.}, at: [<000000007c250a91>] lo_ioctl+0x85/0x1a10 drivers/block/loop.c:1405 #1: (&bdev->bd_mutex){+.+.+.}, at: [<000000004f58ca08>] blkdev_reread_part+0x1f/0x40 block/ioctl.c:189 1 lock held by syz-executor.1/27622: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000062f8c58a>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 2 locks held by blkid/27617: #0: (&bdev->bd_mutex){+.+.+.}, at: [<0000000062f8c58a>] __blkdev_get+0x10e/0xeb0 fs/block_dev.c:1273 #1: (loop_index_mutex){+.+.+.}, at: [<000000004243acde>] lo_open+0x1d/0xb0 drivers/block/loop.c:1622 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 24 Comm: khungtaskd Not tainted 4.9.169+ #42 ffff8801d98d7cc8 ffffffff81b4f7f1 0000000000000001 0000000000000000 0000000000000001 ffffffff81097401 dffffc0000000000 ffff8801d98d7d00 ffffffff81b5aa8c 0000000000000001 0000000000000000 0000000000000001 Call Trace: [<0000000074c8b8bf>] __dump_stack lib/dump_stack.c:15 [inline] [<0000000074c8b8bf>] dump_stack+0xc1/0x120 lib/dump_stack.c:51 [<0000000004768882>] nmi_cpu_backtrace.cold+0x47/0x87 lib/nmi_backtrace.c:99 [<00000000e704ecaa>] nmi_trigger_cpumask_backtrace+0x124/0x155 lib/nmi_backtrace.c:60 [<00000000f74465da>] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [<0000000067c231cc>] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [<0000000067c231cc>] check_hung_task kernel/hung_task.c:125 [inline] [<0000000067c231cc>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [<0000000067c231cc>] watchdog+0x661/0xae0 kernel/hung_task.c:239 [<000000001bb952b1>] kthread+0x278/0x310 kernel/kthread.c:211 [<00000000b94ec16e>] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 20954 Comm: syz-executor.0 Not tainted 4.9.169+ #42 task: 000000000d940e4e task.stack: 00000000d3117d20 RIP: 0033:[<0000000000401584>] c [<000000009c2cd4c0>] 0x401584 RSP: 002b:00007ff73bb5e690 EFLAGS: 00000206 RAX: 00000000391351ff RBX: 000000000000000b RCX: 0000000000458c29 RDX: 0000000000000000 RSI: 00007ff73bb5e6c0 RDI: 000000000000000b RBP: 00000000000000ff R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0101000000000000 R13: 00000000000088fe R14: f07f0000214e000a R15: 0000000000000000 FS: 00007ff73bb5f700(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f1584ffa000 CR3: 00000001d4606000 CR4: 00000000001606b0 DR0: ffffffffffffff00 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000600