INFO: task syz-executor5:12414 blocked for more than 140 seconds. Not tainted 4.20.0-rc7-next-20181224 #188 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D23704 12414 11618 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x9de/0x1ed0 kernel/sched/core.c:3472 schedule+0xef/0x370 kernel/sched/core.c:3516 request_wait_answer+0x4a6/0x900 fs/fuse/dev.c:530 __fuse_request_send+0x12d/0x1d0 fs/fuse/dev.c:550 fuse_request_send+0x62/0xa0 fs/fuse/dev.c:563 fuse_simple_request+0x33d/0x730 fs/fuse/dev.c:621 fuse_access+0x36a/0x500 fs/fuse/dir.c:1077 fuse_permission+0x533/0x5f0 fs/fuse/dir.c:1151 do_inode_permission fs/namei.c:386 [inline] inode_permission+0x35e/0x560 fs/namei.c:451 ksys_chdir+0x10a/0x230 fs/open.c:443 __do_sys_chdir fs/open.c:461 [inline] __se_sys_chdir fs/open.c:459 [inline] __x64_sys_chdir+0x31/0x40 fs/open.c:459 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x457759 Code: 20 84 00 48 8b 88 58 12 00 00 48 85 c9 0f 85 09 01 00 00 48 8d 88 60 12 00 00 48 89 4c 24 28 48 89 0c 24 48 c7 44 24 08 05 00 <00> 00 e8 f0 5d fc ff 48 8b 44 24 18 0f b6 88 c0 00 00 00 84 c9 0f RSP: 002b:00007f52192f6c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000050 RAX: ffffffffffffffda RBX: 0000000000000001 RCX: 0000000000457759 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00000000200000c0 RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00007f52192f76d4 R13: 00000000004bd1a0 R14: 00000000004cdca8 R15: 00000000ffffffff Showing all locks held in the system: 1 lock held by khungtaskd/1033: #0: 000000009b56d70f (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4389 1 lock held by rsyslogd/7895: #0: 000000007d47b002 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:795 2 locks held by getty/8007: #0: 00000000eb8be405 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000cfea014d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 2 locks held by getty/8008: #0: 0000000007a1b5b9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000000429eb8e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 2 locks held by getty/8009: #0: 0000000011b32019 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000f9031868 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 2 locks held by getty/8010: #0: 0000000029972a16 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000081348849 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 2 locks held by getty/8011: #0: 00000000f99da3f1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 0000000076da2fdc (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 2 locks held by getty/8012: #0: 000000004a601477 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000e54381a3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 2 locks held by getty/8013: #0: 00000000329ba60d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000dbb8dab9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1ee0 drivers/tty/n_tty.c:2154 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1033 Comm: khungtaskd Not tainted 4.20.0-rc7-next-20181224 #188 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+0x1d3/0x2c6 lib/dump_stack.c:113 nmi_cpu_backtrace.cold.4+0x63/0xa2 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1c2/0x22c 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:203 [inline] watchdog+0xba1/0x11a0 kernel/hung_task.c:287 kthread+0x35a/0x440 kernel/kthread.c:246 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:57