INFO: task syz-executor.0:16099 blocked for more than 143 seconds. Not tainted 5.1.0-rc4-next-20190409 #21 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.0 D29648 16099 22019 0x00000004 Call Trace: context_switch kernel/sched/core.c:2877 [inline] __schedule+0x817/0x1cc0 kernel/sched/core.c:3518 schedule+0x92/0x180 kernel/sched/core.c:3562 schedule_timeout+0x717/0xc50 kernel/time/timer.c:1783 do_wait_for_common kernel/sched/completion.c:83 [inline] __wait_for_common kernel/sched/completion.c:104 [inline] wait_for_common kernel/sched/completion.c:115 [inline] wait_for_completion+0x29c/0x440 kernel/sched/completion.c:136 __synchronize_srcu+0x197/0x250 kernel/rcu/srcutree.c:921 synchronize_srcu_expedited kernel/rcu/srcutree.c:946 [inline] synchronize_srcu+0x239/0x3e8 kernel/rcu/srcutree.c:997 tracepoint_synchronize_unregister include/linux/tracepoint.h:84 [inline] perf_trace_event_unreg.isra.0+0xcb/0x220 kernel/trace/trace_event_perf.c:163 perf_trace_destroy+0xc1/0x100 kernel/trace/trace_event_perf.c:238 tp_perf_event_destroy+0x16/0x20 kernel/events/core.c:8577 _free_event+0x356/0x13b0 kernel/events/core.c:4453 put_event+0x47/0x60 kernel/events/core.c:4539 perf_event_release_kernel+0x693/0xc60 kernel/events/core.c:4645 perf_release+0x37/0x50 kernel/events/core.c:4655 __fput+0x2e5/0x8d0 fs/file_table.c:278 ____fput+0x16/0x20 fs/file_table.c:309 task_work_run+0x14a/0x1c0 kernel/task_work.c:113 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline] syscall_return_slowpath arch/x86/entry/common.c:268 [inline] do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x412071 Code: 77 24 00 01 00 00 00 c7 05 4c b6 24 00 00 00 00 00 c7 05 22 b6 24 00 00 00 00 00 c6 05 93 77 24 00 01 48 c7 05 8c 77 24 00 00 <04> 00 00 c7 05 7a 77 24 00 01 00 00 00 c7 05 00 b6 24 00 00 00 00 RSP: 002b:00007ffe1c046600 EFLAGS: 00000293 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 0000000000000005 RCX: 0000000000412071 RDX: 0000000000000000 RSI: 0000000000740960 RDI: 0000000000000004 RBP: 0000000000000000 R08: 0000000000740958 R09: 00000000000e8185 R10: 00007ffe1c046520 R11: 0000000000000293 R12: 0000000000000001 R13: 00007ffe1c046640 R14: 0000000000000000 R15: 00007ffe1c046650 Showing all locks held in the system: 1 lock held by khungtaskd/1000: #0: 00000000268d6646 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5061 3 locks held by kworker/1:3/3480: 1 lock held by rsyslogd/7577: #0: 000000003b4f96b2 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/7668: #0: 000000005ce24c16 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000668cf865 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7669: #0: 000000003a87c0e6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000001f56d5c8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7670: #0: 00000000565ca609 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000b64f2be3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7671: #0: 00000000cb6611f4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000a0db65b5 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7672: #0: 0000000073839c3d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000ab76b130 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7673: #0: 0000000039b802c8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000ab45666c (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7674: #0: 000000000a1ae859 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000000f5d4095 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 3 locks held by kworker/u4:15/12068: #0: 00000000d6e70d96 ((wq_completion)netns){+.+.}, at: __write_once_size include/linux/compiler.h:224 [inline] #0: 00000000d6e70d96 ((wq_completion)netns){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000d6e70d96 ((wq_completion)netns){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:855 [inline] #0: 00000000d6e70d96 ((wq_completion)netns){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:40 [inline] #0: 00000000d6e70d96 ((wq_completion)netns){+.+.}, at: set_work_data kernel/workqueue.c:619 [inline] #0: 00000000d6e70d96 ((wq_completion)netns){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:646 [inline] #0: 00000000d6e70d96 ((wq_completion)netns){+.+.}, at: process_one_work+0x87e/0x1790 kernel/workqueue.c:2245 #1: 00000000189e4ad9 (net_cleanup_work){+.+.}, at: process_one_work+0x8b4/0x1790 kernel/workqueue.c:2249 #2: 00000000e760f723 (pernet_ops_rwsem){++++}, at: cleanup_net+0xae/0x960 net/core/net_namespace.c:519 1 lock held by syz-executor.0/16099: #0: 000000001140fdd1 (event_mutex){+.+.}, at: perf_trace_destroy+0x28/0x100 kernel/trace/trace_event_perf.c:236 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1000 Comm: khungtaskd Not tainted 5.1.0-rc4-next-20190409 #21 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+0x172/0x1f0 lib/dump_stack.c:113 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1be/0x236 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:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:204 [inline] watchdog+0x9b7/0xec0 kernel/hung_task.c:288 kthread+0x357/0x430 kernel/kthread.c:254 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: