INFO: task syz-executor5:610 blocked for more than 140 seconds. Not tainted 4.20.0-rc1-next-20181107+ #107 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor5 D18616 610 1 0x00000004 Call Trace: context_switch kernel/sched/core.c:2831 [inline] __schedule+0x8cf/0x21d0 kernel/sched/core.c:3472 schedule+0xfe/0x460 kernel/sched/core.c:3516 __rwsem_down_write_failed_common+0xc9a/0x15e0 kernel/locking/rwsem-xadd.c:577 rwsem_down_write_failed+0xe/0x10 kernel/locking/rwsem-xadd.c:606 call_rwsem_down_write_failed+0x17/0x30 arch/x86/lib/rwsem.S:117 __down_write arch/x86/include/asm/rwsem.h:142 [inline] down_write+0xa5/0x130 kernel/locking/rwsem.c:72 inode_lock include/linux/fs.h:764 [inline] vfs_unlink+0xd1/0x510 fs/namei.c:3991 do_unlinkat+0x6cc/0xa30 fs/namei.c:4063 __do_sys_unlink fs/namei.c:4110 [inline] __se_sys_unlink fs/namei.c:4108 [inline] __x64_sys_unlink+0x42/0x50 fs/namei.c:4108 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x4572b7 Code: cc cc cc 64 48 8b 0c 25 f8 ff ff ff 48 3b 61 10 76 29 48 83 ec 10 48 89 6c 24 08 48 8d 6c 24 08 48 8b 42 08 48 8b 40 08 48 89 <04> 24 e8 02 d3 fc ff 48 8b 6c 24 08 48 83 c4 10 c3 e8 e3 2b 00 00 RSP: 002b:00007ffeaeab24f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000057 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00000000004572b7 RDX: 00007ffeaeab2510 RSI: 00007ffeaeab2510 RDI: 00007ffeaeab25a0 RBP: 0000000000000288 R08: 0000000000000000 R09: 000000000000000a R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffeaeab3630 R13: 0000000001922940 R14: 0000000000000000 R15: 0000000000000005 Showing all locks held in the system: 1 lock held by khungtaskd/1007: #0: 00000000382d9244 (rcu_read_lock){....}, at: debug_show_all_locks+0xd0/0x424 kernel/locking/lockdep.c:4379 1 lock held by rsyslogd/5597: #0: 000000004b362801 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x1bb/0x200 fs/file.c:766 2 locks held by getty/5687: #0: 0000000012ae5805 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000c908797f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5688: #0: 0000000024525eac (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000020929d3 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5689: #0: 000000009d2dace1 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 000000001d877fd6 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5690: #0: 0000000093aecc89 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000c027b7fa (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5691: #0: 000000001c0c73f8 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 0000000080c78266 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5692: #0: 000000009abcce15 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000cd9f53a9 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 2 locks held by getty/5693: #0: 000000002f53e6d4 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:353 #1: 00000000ea3bcd95 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x335/0x1e80 drivers/tty/n_tty.c:2154 3 locks held by syz-executor5/610: #0: 00000000f61ba007 (sb_writers#3){.+.+}, at: sb_start_write include/linux/fs.h:1607 [inline] #0: 00000000f61ba007 (sb_writers#3){.+.+}, at: mnt_want_write+0x3f/0xc0 fs/namespace.c:359 #1: 00000000a9f9dd1f (&type->i_mutex_dir_key#3/1){+.+.}, at: inode_lock_nested include/linux/fs.h:799 [inline] #1: 00000000a9f9dd1f (&type->i_mutex_dir_key#3/1){+.+.}, at: do_unlinkat+0x3d8/0xa30 fs/namei.c:4049 #2: 0000000093f7af6c (&sb->s_type->i_mutex_key#10){++++}, at: inode_lock include/linux/fs.h:764 [inline] #2: 0000000093f7af6c (&sb->s_type->i_mutex_key#10){++++}, at: vfs_unlink+0xd1/0x510 fs/namei.c:3991 2 locks held by syz-executor5/3413: #0: 00000000f61ba007 (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2828 [inline] #0: 00000000f61ba007 (sb_writers#3){.+.+}, at: vfs_write+0x42a/0x560 fs/read_write.c:548 #1: 0000000093f7af6c (&sb->s_type->i_mutex_key#10){++++}, at: inode_trylock include/linux/fs.h:784 [inline] #1: 0000000093f7af6c (&sb->s_type->i_mutex_key#10){++++}, at: ext4_file_write_iter+0x2a1/0x1420 fs/ext4/file.c:232 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 1007 Comm: khungtaskd Not tainted 4.20.0-rc1-next-20181107+ #107 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+0x244/0x39d lib/dump_stack.c:113 nmi_cpu_backtrace.cold.2+0x5c/0xa1 lib/nmi_backtrace.c:101 nmi_trigger_cpumask_backtrace+0x1e8/0x22a 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:144 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline] watchdog+0xb4c/0x1060 kernel/hung_task.c:289 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