INFO: task syz-executor.2:7717 blocked for more than 143 seconds. Not tainted 5.1.0-rc7-next-20190506 #1 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. syz-executor.2 D23920 7717 1 0x80004004 Call Trace: context_switch kernel/sched/core.c:2817 [inline] __schedule+0x7d1/0x1580 kernel/sched/core.c:3444 schedule+0xa8/0x260 kernel/sched/core.c:3508 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3567 __mutex_lock_common kernel/locking/mutex.c:1002 [inline] __mutex_lock+0x726/0x1310 kernel/locking/mutex.c:1072 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087 acct_get kernel/acct.c:161 [inline] slow_acct_process kernel/acct.c:577 [inline] acct_process+0x2e5/0x61e kernel/acct.c:605 do_exit+0x17bd/0x2fa0 kernel/exit.c:866 do_group_exit+0x135/0x370 kernel/exit.c:980 get_signal+0x425/0x2270 kernel/signal.c:2638 do_signal+0x87/0x1900 arch/x86/kernel/signal.c:815 exit_to_usermode_loop+0x244/0x2c0 arch/x86/entry/common.c:163 prepare_exit_to_usermode arch/x86/entry/common.c:198 [inline] syscall_return_slowpath arch/x86/entry/common.c:276 [inline] do_syscall_64+0x57e/0x670 arch/x86/entry/common.c:301 entry_SYSCALL_64_after_hwframe+0x49/0xbe RIP: 0033:0x412dea Code: 31 d2 e8 39 f3 ff ff 44 8b 6c 24 20 e9 34 fe ff ff 41 89 c0 89 c6 48 8b 4c 24 10 ba 20 3b 44 00 31 ff 31 c0 ff 15 5e 68 24 00 8e fc ff ff bd fa ff ff ff e9 84 fc ff ff 48 8d bb c8 00 00 00 RSP: 002b:00007ffc5211e7d8 EFLAGS: 00000246 ORIG_RAX: 000000000000003d RAX: fffffffffffffe00 RBX: 00005555556c4940 RCX: 0000000000412dea RDX: 0000000040000000 RSI: 00007ffc5211e810 RDI: ffffffffffffffff RBP: 00000000000026e7 R08: 0000000000000001 R09: 0000000000000001 R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000000a R13: 00007ffc5211e810 R14: 00005555556c499b R15: 00007ffc5211e820 Showing all locks held in the system: 1 lock held by khungtaskd/1043: #0: 00000000a4fde072 (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:5148 1 lock held by rsyslogd/7541: #0: 00000000e5418d57 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:801 2 locks held by getty/7631: #0: 0000000006f02401 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000005a825661 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7632: #0: 00000000867bdf52 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000008ecccc60 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7633: #0: 00000000defeff57 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000009be3ca09 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7634: #0: 00000000d4c03b2d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000007ad39dcb (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7635: #0: 000000006a41ee0d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 000000002165fb97 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7636: #0: 00000000099e5cda (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000ad7de978 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 2 locks held by getty/7637: #0: 00000000368cc1b6 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:341 #1: 00000000140280bd (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b70 drivers/tty/n_tty.c:2156 1 lock held by syz-executor.2/7717: #0: 0000000056354126 (&acct->lock#2){+.+.}, at: acct_get kernel/acct.c:161 [inline] #0: 0000000056354126 (&acct->lock#2){+.+.}, at: slow_acct_process kernel/acct.c:577 [inline] #0: 0000000056354126 (&acct->lock#2){+.+.}, at: acct_process+0x2e5/0x61e kernel/acct.c:605 2 locks held by kworker/u4:4/24243: #0: 0000000090a0628a (&rq->lock){-.-.}, at: rq_lock kernel/sched/sched.h:1168 [inline] #0: 0000000090a0628a (&rq->lock){-.-.}, at: __schedule+0x1f5/0x1580 kernel/sched/core.c:3396 #1: 00000000a4fde072 (rcu_read_lock){....}, at: __update_idle_core+0x45/0x3f0 kernel/sched/fair.c:6087 5 locks held by syz-executor.2/5699: #0: 0000000056354126 (&acct->lock#2){+.+.}, at: acct_get kernel/acct.c:161 [inline] #0: 0000000056354126 (&acct->lock#2){+.+.}, at: slow_acct_process kernel/acct.c:577 [inline] #0: 0000000056354126 (&acct->lock#2){+.+.}, at: acct_process+0x2e5/0x61e kernel/acct.c:605 #1: 00000000f546f1a2 (sb_writers#15){.+.+}, at: file_start_write_trylock include/linux/fs.h:2843 [inline] #1: 00000000f546f1a2 (sb_writers#15){.+.+}, at: do_acct_process+0xf37/0x1150 kernel/acct.c:517 #2: 000000001cf73d02 (&ovl_i_mutex_key[depth]){+.+.}, at: inode_lock include/linux/fs.h:778 [inline] #2: 000000001cf73d02 (&ovl_i_mutex_key[depth]){+.+.}, at: ovl_write_iter+0x148/0xc20 fs/overlayfs/file.c:231 #3: 00000000bdb96ceb (sb_writers#3){.+.+}, at: file_start_write include/linux/fs.h:2836 [inline] #3: 00000000bdb96ceb (sb_writers#3){.+.+}, at: ovl_write_iter+0x91b/0xc20 fs/overlayfs/file.c:243 #4: 00000000d347f02d (&sb->s_type->i_mutex_key#10){++++}, at: inode_trylock include/linux/fs.h:798 [inline] #4: 00000000d347f02d (&sb->s_type->i_mutex_key#10){++++}, at: ext4_file_write_iter+0x257/0x11c0 fs/ext4/file.c:232 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1043 Comm: khungtaskd Not tainted 5.1.0-rc7-next-20190506 #1 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+0x9b7/0xec0 kernel/hung_task.c:288 kthread+0x357/0x430 kernel/kthread.c:254 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:352 Sending NMI from CPU 1 to CPUs 0: