INFO: task syz-executor2:18596 blocked for more than 140 seconds. Not tainted 5.0.0-rc4-next-20190201 #24 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor2 D28432 18596 7519 0x00000004 Call Trace: context_switch kernel/sched/core.c:2847 [inline] __schedule+0x817/0x1cc0 kernel/sched/core.c:3488 schedule+0x92/0x180 kernel/sched/core.c:3532 request_wait_answer+0x42f/0x7c0 fs/fuse/dev.c:554 __fuse_request_send+0x12b/0x1d0 fs/fuse/dev.c:574 fuse_request_send+0x60/0xa0 fs/fuse/dev.c:587 fuse_simple_request+0x2f6/0x730 fs/fuse/dev.c:645 fuse_do_getattr+0x24b/0xc80 fs/fuse/dir.c:895 fuse_perm_getattr+0x3d/0x60 fs/fuse/dir.c:1078 fuse_permission+0x3d5/0x530 fs/fuse/dir.c:1115 do_inode_permission fs/namei.c:386 [inline] inode_permission+0x36d/0x570 fs/namei.c:451 may_lookup fs/namei.c:1702 [inline] link_path_walk.part.0+0x9d6/0x1340 fs/namei.c:2084 link_path_walk fs/namei.c:2072 [inline] path_openat+0x202/0x46e0 fs/namei.c:3534 do_filp_open+0x1a1/0x280 fs/namei.c:3565 do_sys_open+0x3fe/0x5d0 fs/open.c:1063 __do_sys_openat fs/open.c:1090 [inline] __se_sys_openat fs/open.c:1084 [inline] __x64_sys_openat+0x9d/0x100 fs/open.c:1084 do_syscall_64+0x103/0x610 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457e39 Code: 44 24 18 00 00 00 00 e8 a5 b0 fc ff 48 8b 44 24 38 48 89 04 24 e8 d7 77 fb ff 48 8b 6c 24 40 48 83 c4 48 c3 48 89 d1 eb 90 e8 <73> 20 00 00 e9 7e fe ff ff cc cc cc cc cc cc cc cc cc cc cc cc cc RSP: 002b:00007fcfbc71bc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000457e39 RDX: 0000000000000002 RSI: 0000000020000180 RDI: ffffffffffffff9c RBP: 000000000073bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007fcfbc71c6d4 R13: 00000000004c3f00 R14: 00000000004d7268 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1040: #0: 0000000065c5816b (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4374 2 locks held by kworker/u4:4/2534: #0: 00000000d0a7ddc4 (&rq->lock){-.-.}, at: idle_balance kernel/sched/fair.c:9948 [inline] #0: 00000000d0a7ddc4 (&rq->lock){-.-.}, at: pick_next_task_fair+0x10f3/0x1860 kernel/sched/fair.c:7019 #1: 0000000065c5816b (rcu_read_lock){....}, at: __update_idle_core+0x45/0x3f0 kernel/sched/fair.c:6016 1 lock held by rsyslogd/7387: 2 locks held by getty/7477: #0: 000000004bfc0580 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000004acbbd55 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7478: #0: 00000000c8453c32 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000d58ed6d7 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7479: #0: 0000000004b4e90b (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000dd0f7107 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7480: #0: 0000000053869b94 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000869dad75 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7481: #0: 0000000000acf756 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000a8dff86b (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7482: #0: 000000009d793132 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000ddc0aa03 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7483: #0: 000000008a82990a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000004973d1c9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1040 Comm: khungtaskd Not tainted 5.0.0-rc4-next-20190201 #24 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+0x9df/0xee0 kernel/hung_task.c:288 kthread+0x357/0x430 kernel/kthread.c:247 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: