INFO: task syz-executor6:3439 blocked for more than 140 seconds. Not tainted 4.9.119-g9dc978d #23 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor6 D27176 3439 2840 0x00000004 ffff8801d8531800 ffff880199572a00 ffff8801d8a0c000 ffff88019c73e000 ffff8801db221c18 ffff88018b637660 ffffffff839ebdcd dffffc0000000000 ffff88019242bc90 ffff88018b637620 00ff8801d85320c0 ffff8801db2224e8 Call Trace: [] schedule+0x7f/0x1b0 kernel/sched/core.c:3553 [] d_wait_lookup fs/dcache.c:2455 [inline] [] d_alloc_parallel+0xeb2/0x17c0 fs/dcache.c:2537 [] lookup_slow+0x19c/0x470 fs/namei.c:1650 [] walk_component+0x716/0x1bb0 fs/namei.c:1784 [] lookup_last fs/namei.c:2266 [inline] [] path_lookupat.isra.41+0x186/0x410 fs/namei.c:2283 [] filename_lookup.part.55+0x177/0x370 fs/namei.c:2317 [] filename_lookup fs/namei.c:2310 [inline] [] user_path_at_empty+0x53/0x70 fs/namei.c:2578 [] user_path_at include/linux/namei.h:55 [inline] [] do_utimes+0x17f/0x2c0 fs/utimes.c:155 [] SYSC_futimesat fs/utimes.c:214 [inline] [] SyS_futimesat fs/utimes.c:189 [inline] [] SYSC_utimes fs/utimes.c:220 [inline] [] SyS_utimes+0x13d/0x1b0 fs/utimes.c:217 [] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282 [] entry_SYSCALL_64_after_swapgs+0x5d/0xdb Showing all locks held in the system: 2 locks held by khungtaskd/519: #0: (rcu_read_lock){......}, at: [] check_hung_uninterruptible_tasks kernel/hung_task.c:168 [inline] #0: (rcu_read_lock){......}, at: [] watchdog+0x11c/0xa20 kernel/hung_task.c:239 #1: (tasklist_lock){.+.+..}, at: [] debug_show_all_locks+0x79/0x218 kernel/locking/lockdep.c:4336 2 locks held by rs:main Q:Reg/3563: #0: (&f->f_pos_lock){+.+.+.}, at: [] __fdget_pos+0xac/0xd0 fs/file.c:781 #1: (sb_writers#3){.+.+.+}, at: [] file_start_write include/linux/fs.h:2640 [inline] #1: (sb_writers#3){.+.+.+}, at: [] vfs_write+0x3ae/0x530 fs/read_write.c:556 1 lock held by rsyslogd/3565: #0: (&f->f_pos_lock){+.+.+.}, at: [] __fdget_pos+0xac/0xd0 fs/file.c:781 2 locks held by getty/3661: #0: (&tty->ldisc_sem){++++++}, at: [] ldsem_down_read+0x32/0x40 drivers/tty/tty_ldsem.c:367 #1: (&ldata->atomic_read_lock){+.+...}, at: [] n_tty_read+0x202/0x16e0 drivers/tty/n_tty.c:2142 1 lock held by syz-executor6/3390: #0: (&sb->s_type->i_mutex_key#21){++++++}, at: [] inode_lock_shared include/linux/fs.h:776 [inline] #0: (&sb->s_type->i_mutex_key#21){++++++}, at: [] lookup_slow+0x141/0x470 fs/namei.c:1645 1 lock held by syz-executor6/3439: #0: (&sb->s_type->i_mutex_key#21){++++++}, at: [] inode_lock_shared include/linux/fs.h:776 [inline] #0: (&sb->s_type->i_mutex_key#21){++++++}, at: [] lookup_slow+0x141/0x470 fs/namei.c:1645 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 519 Comm: khungtaskd Not tainted 4.9.119-g9dc978d #23 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 ffff8801d8567d08 ffffffff81eb4be9 0000000000000000 0000000000000001 0000000000000001 0000000000000001 ffffffff810b9bd0 ffff8801d8567d40 ffffffff81ebfee7 0000000000000001 0000000000000000 0000000000000003 Call Trace: [] __dump_stack lib/dump_stack.c:15 [inline] [] dump_stack+0xc1/0x128 lib/dump_stack.c:51 [] nmi_cpu_backtrace.cold.2+0x48/0x87 lib/nmi_backtrace.c:99 [] nmi_trigger_cpumask_backtrace+0x12a/0x14f lib/nmi_backtrace.c:60 [] arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:37 [] trigger_all_cpu_backtrace include/linux/nmi.h:58 [inline] [] check_hung_task kernel/hung_task.c:125 [inline] [] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline] [] watchdog+0x6b4/0xa20 kernel/hung_task.c:239 [] kthread+0x26d/0x300 kernel/kthread.c:211 [] ret_from_fork+0x5c/0x70 arch/x86/entry/entry_64.S:373 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at pc 0xffffffff839fb8d6