audit: type=1400 audit(1520925421.236:32175): avc: denied { map } for pid=12091 comm="sh" path="/bin/dash" dev="sda1" ino=1473 scontext=system_u:system_r:insmod_t:s0-s0:c0.c1023 tcontext=system_u:object_r:file_t:s0 tclass=file permissive=1 unregister_netdevice: waiting for lo to become free. Usage count = 6 unregister_netdevice: waiting for lo to become free. Usage count = 6 INFO: task syz-executor3:12034 blocked for more than 120 seconds. Not tainted 4.16.0-rc5+ #262 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor3 D24112 12034 4281 0x20020004 Call Trace: context_switch kernel/sched/core.c:2862 [inline] __schedule+0x8fb/0x1ec0 kernel/sched/core.c:3440 schedule+0xf5/0x430 kernel/sched/core.c:3499 io_schedule+0x1c/0x70 kernel/sched/core.c:5115 wait_on_page_bit_common mm/filemap.c:1099 [inline] __lock_page+0x574/0x720 mm/filemap.c:1272 unregister_netdevice: waiting for lo to become free. Usage count = 6 lock_page include/linux/pagemap.h:483 [inline] truncate_inode_pages_range+0x197c/0x1fe0 mm/truncate.c:448 blk_ioctl_discard+0x240/0x340 block/ioctl.c:228 blkdev_ioctl+0xc00/0x1e00 block/ioctl.c:527 compat_blkdev_ioctl+0xd3a/0x1840 block/compat_ioctl.c:357 C_SYSC_ioctl fs/compat_ioctl.c:1461 [inline] compat_SyS_ioctl+0x151/0x2a30 fs/compat_ioctl.c:1407 do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline] do_fast_syscall_32+0x3ec/0xf9f arch/x86/entry/common.c:392 entry_SYSENTER_compat+0x70/0x7f arch/x86/entry/entry_64_compat.S:139 RIP: 0023:0xf7f97c99 RSP: 002b:00000000f779309c EFLAGS: 00000286 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 0000000000000013 RCX: 000000000000127d RDX: 0000000020000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Showing all locks held in the system: 2 locks held by khungtaskd/799: #0: (rcu_read_lock){....}, at: [<000000004a6a9451>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] #0: (rcu_read_lock){....}, at: [<000000004a6a9451>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249 #1: (tasklist_lock){.+.+}, at: [<000000000e9bbb82>] debug_show_all_locks+0xd3/0x3d0 kernel/locking/lockdep.c:4470 1 lock held by rsyslogd/4082: #0: (&f->f_pos_lock){+.+.}, at: [<00000000a288164e>] __fdget_pos+0x12b/0x190 fs/file.c:765 2 locks held by getty/4205: #0: (&tty->ldisc_sem){++++}, at: [<0000000001fdaaa2>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004b610755>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4206: #0: (&tty->ldisc_sem){++++}, at: [<0000000001fdaaa2>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004b610755>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4207: #0: (&tty->ldisc_sem){++++}, at: [<0000000001fdaaa2>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004b610755>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4208: #0: (&tty->ldisc_sem){++++}, at: [<0000000001fdaaa2>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004b610755>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4209: #0: (&tty->ldisc_sem){++++}, at: [<0000000001fdaaa2>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004b610755>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 2 locks held by getty/4210: #0: (&tty->ldisc_sem){++++}, at: [<0000000001fdaaa2>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004b610755>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 3 locks held by kworker/u4:5/10323: #0: ((wq_completion)"%s""netns"){+.+.}, at: [<000000002a6021bb>] work_static include/linux/workqueue.h:198 [inline] #0: ((wq_completion)"%s""netns"){+.+.}, at: [<000000002a6021bb>] set_work_data kernel/workqueue.c:619 [inline] #0: ((wq_completion)"%s""netns"){+.+.}, at: [<000000002a6021bb>] set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: ((wq_completion)"%s""netns"){+.+.}, at: [<000000002a6021bb>] process_one_work+0xb12/0x1bb0 kernel/workqueue.c:2084 #1: (net_cleanup_work){+.+.}, at: [<00000000229ff353>] process_one_work+0xb89/0x1bb0 kernel/workqueue.c:2088 #2: (net_mutex){+.+.}, at: [<000000001bf10e3f>] cleanup_net+0x242/0xcb0 net/core/net_namespace.c:484 2 locks held by getty/25526: #0: (&tty->ldisc_sem){++++}, at: [<0000000001fdaaa2>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: (&ldata->atomic_read_lock){+.+.}, at: [<000000004b610755>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 799 Comm: khungtaskd Not tainted 4.16.0-rc5+ #262 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+0x194/0x24d lib/dump_stack.c:53 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x123/0x180 lib/nmi_backtrace.c:62 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline] check_hung_task kernel/hung_task.c:132 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline] watchdog+0x90c/0xd60 kernel/hung_task.c:249 kthread+0x33c/0x400 kernel/kthread.c:238 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:406 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54