INFO: task syz-executor6:1661 blocked for more than 140 seconds. Not tainted 4.18.0-rc8+ #182 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor6 D23672 1661 4471 0x00000004 Call Trace: context_switch kernel/sched/core.c:2853 [inline] __schedule+0x87c/0x1ec0 kernel/sched/core.c:3501 schedule+0xfb/0x450 kernel/sched/core.c:3545 schedule_timeout+0x1cc/0x260 kernel/time/timer.c:1777 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+0x430/0x8d0 kernel/sched/completion.c:136 flush_work+0x531/0x900 kernel/workqueue.c:2918 __cancel_work_timer+0x4bd/0x830 kernel/workqueue.c:2989 cancel_work_sync+0x17/0x20 kernel/workqueue.c:3025 p9_conn_destroy net/9p/trans_fd.c:860 [inline] p9_fd_close+0x36a/0x5b0 net/9p/trans_fd.c:886 p9_client_create+0xa9a/0x1770 net/9p/client.c:1077 v9fs_session_init+0x21a/0x1a80 fs/9p/v9fs.c:400 v9fs_mount+0x7c/0x900 fs/9p/vfs_super.c:135 mount_fs+0xae/0x328 fs/super.c:1277 vfs_kern_mount.part.34+0xdc/0x4e0 fs/namespace.c:1037 vfs_kern_mount fs/namespace.c:1027 [inline] do_new_mount fs/namespace.c:2518 [inline] do_mount+0x581/0x30e0 fs/namespace.c:2848 ksys_mount+0x12d/0x140 fs/namespace.c:3064 __do_sys_mount fs/namespace.c:3078 [inline] __se_sys_mount fs/namespace.c:3075 [inline] __x64_sys_mount+0xbe/0x150 fs/namespace.c:3075 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457089 Code: 08 e8 3b a9 fb ff 48 8b 44 24 20 48 8b 4c 24 18 48 8b 54 24 38 48 8b 7c 24 48 eb 8d 48 8b 6c 24 50 48 83 c4 58 c3 48 89 04 24 <48> 89 5c 24 08 e8 0d a9 fb ff 48 8b 44 24 40 48 8b 4c 24 48 48 8b RSP: 002b:00007fa03f49ac78 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007fa03f49b6d4 RCX: 0000000000457089 RDX: 0000000020000340 RSI: 00000000200000c0 RDI: 0000000000000000 RBP: 00000000009301e0 R08: 00000000200001c0 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004d2310 R14: 00000000004c7a36 R15: 0000000000000002 Showing all locks held in the system: 1 lock held by khungtaskd/773: #0: 000000003cc831ee (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x428 kernel/locking/lockdep.c:4461 2 locks held by kworker/0:3/2045: #0: 00000000be4197e7 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline] #0: 00000000be4197e7 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: 00000000be4197e7 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] #0: 00000000be4197e7 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:59 [inline] #0: 00000000be4197e7 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline] #0: 00000000be4197e7 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] #0: 00000000be4197e7 ((wq_completion)"events"){+.+.}, at: process_one_work+0xb44/0x1ba0 kernel/workqueue.c:2124 #1: 0000000011aed6c0 ((work_completion)(&m->wq)){+.+.}, at: process_one_work+0xb9b/0x1ba0 kernel/workqueue.c:2128 1 lock held by rsyslogd/4331: #0: 00000000d6c33e36 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/4422: #0: 00000000517775b8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000fe183fc2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4423: #0: 000000000ccbba36 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000000f2b11bf (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4424: #0: 00000000e32bfa31 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 000000004e96b59b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4425: #0: 00000000b9b4ccc0 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000059a03cb8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4426: #0: 0000000093961447 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000af168690 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4427: #0: 00000000bffc434d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 00000000c338a11d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 2 locks held by getty/4428: #0: 00000000b94e9cd6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365 #1: 0000000053449127 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ce0 drivers/tty/n_tty.c:2140 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 773 Comm: khungtaskd Not tainted 4.18.0-rc8+ #182 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 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103 nmi_trigger_cpumask_backtrace+0x151/0x192 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_uninterruptible_tasks kernel/hung_task.c:196 [inline] watchdog+0x9c4/0xf80 kernel/hung_task.c:252 kthread+0x345/0x410 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 10 Comm: rcu_sched Not tainted 4.18.0-rc8+ #182 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 RIP: 0010:bytes_is_nonzero mm/kasan/kasan.c:166 [inline] RIP: 0010:memory_is_nonzero mm/kasan/kasan.c:184 [inline] RIP: 0010:memory_is_poisoned_n mm/kasan/kasan.c:210 [inline] RIP: 0010:memory_is_poisoned mm/kasan/kasan.c:241 [inline] RIP: 0010:check_memory_region_inline mm/kasan/kasan.c:257 [inline] RIP: 0010:check_memory_region+0x126/0x1b0 mm/kasan/kasan.c:267 Code: ff ff 4d 85 c0 74 ba 48 b8 01 00 00 00 00 fc ff df 4d 01 c8 48 01 d8 41 80 39 00 74 08 e9 8c 00 00 00 48 89 d8 4c 39 c0 74 97 <80> 38 00 48 8d 58 01 74 ef eb 87 4c 89 c0 49 39 c2 74 59 e8 42 0f RSP: 0018:ffff8801d9ebe640 EFLAGS: 00000097 RAX: ffffed003b3d7d06 RBX: ffffed003b3d7d06 RCX: ffffffff815940de RDX: 0000000000000001 RSI: 0000000000000050 RDI: ffff8801d9ebe810 RBP: ffff8801d9ebe658 R08: ffffed003b3d7d0c R09: ffffed003b3d7d02 R10: ffffed003b3d7d0b R11: ffff8801d9ebe85f R12: ffffed003b3d7d0c R13: 0000000000000000 R14: ffff8801d9ebea28 R15: 0000000000000001 FS: 0000000000000000(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: ffffffffff600400 CR3: 00000001cbc6a000 CR4: 00000000001406e0 Call Trace: memset+0x23/0x40 mm/kasan/kasan.c:285 memset include/linux/string.h:330 [inline] update_sg_lb_stats kernel/sched/fair.c:8125 [inline] update_sd_lb_stats+0x3ee/0x2c50 kernel/sched/fair.c:8309 find_busiest_group+0x100/0x1cb0 kernel/sched/fair.c:8580 load_balance+0x655/0x3640 kernel/sched/fair.c:8845 idle_balance kernel/sched/fair.c:9808 [inline] pick_next_task_fair+0x5b6/0x17a0 kernel/sched/fair.c:7017 pick_next_task kernel/sched/core.c:3347 [inline] __schedule+0x49e/0x1ec0 kernel/sched/core.c:3475 schedule+0xfb/0x450 kernel/sched/core.c:3545 schedule_timeout+0x140/0x260 kernel/time/timer.c:1801 rcu_gp_kthread+0x717/0x1c90 kernel/rcu/tree.c:2179 kthread+0x345/0x410 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 INFO: NMI handler (nmi_cpu_backtrace_handler) took too long to run: 1.496 msecs